diff --git a/includes/admin.form.inc b/includes/admin.form.inc
index 51116f5c..cf0b8f69 100644
--- a/includes/admin.form.inc
+++ b/includes/admin.form.inc
@@ -74,6 +74,12 @@ function islandora_repository_admin(array $form, array &$form_state) {
           '#description' => t('Displays an extra print tab, allowing an object to be printed'),
           '#default_value' => variable_get('islandora_show_print_option', FALSE),
         ),
+        'islandora_render_drupal_breadcrumbs' => array(
+          '#type' => 'checkbox',
+          '#title' => t('Render Drupal breadcrumbs'),
+          '#description' => t('Larger sites may experience a notable performance improvement when disabled due to how breadcrumbs are constructed.'),
+          '#default_value' => variable_get('islandora_render_drupal_breadcrumbs', TRUE),
+        ),
       ),
       'islandora_namespace' => array(
         '#type' => 'fieldset',
diff --git a/includes/breadcrumb.inc b/includes/breadcrumb.inc
index e3eb2782..38c0970e 100644
--- a/includes/breadcrumb.inc
+++ b/includes/breadcrumb.inc
@@ -25,10 +25,13 @@
  *   drupal_set_breadcrumb().
  */
 function islandora_get_breadcrumbs($object) {
-  $breadcrumbs = islandora_get_breadcrumbs_recursive($object->id, $object->repository);
-  array_pop($breadcrumbs);
-  $context = 'islandora';
-  drupal_alter('islandora_breadcrumbs', $breadcrumbs, $context, $object);
+  $breadcrumbs = array();
+  if (variable_get('islandora_render_drupal_breadcrumbs', TRUE)) {
+    $breadcrumbs = islandora_get_breadcrumbs_recursive($object->id, $object->repository);
+    array_pop($breadcrumbs);
+    $context = 'islandora';
+    drupal_alter('islandora_breadcrumbs', $breadcrumbs, $context, $object);
+  }
   return $breadcrumbs;
 }
 
diff --git a/includes/delete_datastream.form.inc b/includes/delete_datastream.form.inc
index ce1959df..b88ef0da 100644
--- a/includes/delete_datastream.form.inc
+++ b/includes/delete_datastream.form.inc
@@ -19,15 +19,44 @@
  *   The drupal form definition.
  */
 function islandora_delete_datastream_form(array $form, array &$form_state, AbstractDatastream $datastream) {
+  // XXX: Stashed version of datastream is deprecated... Use object and
+  // datastream IDs from 'datastream_info' to acquire.
   $form_state['datastream'] = $datastream;
+
+  $form_state['datastream_info'] = array(
+    'object_id' => $datastream->parent->id,
+    'datastream_id' => $datastream->id,
+  );
   $object = $datastream->parent;
   $dsid = $datastream->id;
-  $derivs = implode(', ', islandora_datastream_to_purge($object, $dsid));
+  $dsids = array_merge(array($dsid), islandora_datastream_to_purge($object, $dsid));
+  $dsids = array_unique($dsids);
   $form['delete_derivatives'] = array(
     '#title' => t('Delete Derviatives'),
     '#type' => 'checkbox',
     '#default_value' => 0,
-    '#description' => t('Derivatives can be regenerated at a later time. <p><strong>Datastream(s) to be purged: </strong></p>@dsid, @derivs', array('@dsid' => $datastream->id, '@derivs' => $derivs)),
+    '#description' => t('Derivatives can be regenerated at a later time.'),
+  );
+  $form['base_info'] = array(
+    '#type' => 'item',
+    '#title' => t('Datastream to be purged'),
+    '#markup' => $dsid,
+    '#states' => array(
+      'invisible' => array(
+        ':input[name="delete_derivatives"]' => array('checked' => TRUE),
+      ),
+    ),
+  );
+  $form['derivative_info'] = array(
+    '#type' => 'item',
+    '#title' => t('Datastream(s) to be purged'),
+    '#description' => t('Including detectable derivatives.'),
+    '#markup' => implode(', ', $dsids),
+    '#states' => array(
+      'visible' => array(
+        ':input[name="delete_derivatives"]' => array('checked' => TRUE),
+      ),
+    ),
   );
   return confirm_form($form,
     t('Are you sure you want to delete the %dsid datastream?', array('%dsid' => $datastream->id)),
@@ -87,9 +116,10 @@ function islandora_datastream_derivatives_purged(AbstractObject $object, $dsid)
  *   The Drupal form state.
  */
 function islandora_delete_datastream_form_submit(array $form, array &$form_state) {
-  $datastream = $form_state['datastream'];
-  $datastream_id = $datastream->id;
-  $object = $datastream->parent;
+  $object = islandora_object_load($form_state['datastream_info']['object_id']);
+  $datastream_id = $form_state['datastream_info']['datastream_id'];
+  $datastream = $object[$datastream_id];
+
   $deleted = FALSE;
   if ($form_state['values']['delete_derivatives']) {
     islandora_datastream_derivatives_purged($object, $datastream_id);
diff --git a/includes/tuque_wrapper.inc b/includes/tuque_wrapper.inc
index d14a86b3..ef2a2991 100644
--- a/includes/tuque_wrapper.inc
+++ b/includes/tuque_wrapper.inc
@@ -56,7 +56,7 @@ function islandora_alter_datastream(AbstractObject $object, AbstractDatastream $
 }
 
 /**
- * Constructs a list of hooks from the given paramenters and invokes them.
+ * Constructs a list of hooks from the given parameters and invokes them.
  */
 function islandora_invoke_object_hooks($hook, array $models) {
   module_load_include('inc', 'islandora', 'includes/utilities');
@@ -64,7 +64,7 @@ function islandora_invoke_object_hooks($hook, array $models) {
 }
 
 /**
- * Constructs a list of hooks from the given paramenters and invokes them.
+ * Constructs a list of hooks from the given parameters and invokes them.
  */
 function islandora_invoke_datastream_hooks($hook, array $models, $dsid) {
   module_load_include('inc', 'islandora', 'includes/utilities');
@@ -233,6 +233,54 @@ class IslandoraFedoraObject extends FedoraObject {
       throw $e;
     }
   }
+
+  /**
+   * Purge a datastream.
+   *
+   * Invokes datastream altered/purged hooks and calls the API-M method.
+   *
+   * @see FedoraObject::purgeObject()
+   */
+  public function purgeDatastream($id) {
+    $this->populateDatastreams();
+
+    if (!array_key_exists($id, $this->datastreams)) {
+      return FALSE;
+    }
+    $context = array(
+      'action' => 'purge',
+      'purge' => TRUE,
+      'delete' => FALSE,
+      'block' => FALSE,
+    );
+    try {
+      islandora_alter_datastream($this, $this[$id], $context);
+      $action = $context['block'] ? 'block' : FALSE;
+      $action = (!$action && $context['delete']) ? 'delete' : $action;
+      $action = !$action ? 'purge' : $action;
+      switch ($action) {
+        case 'block':
+          throw new Exception('Purge Datastream was blocked.');
+
+        case 'delete':
+          $this[$id]->state = 'D';
+          return array();
+
+        default:
+          $to_return = parent::purgeDatastream($id);
+          islandora_invoke_datastream_hooks(ISLANDORA_DATASTREAM_PURGED_HOOK, $this->models, $id, $this, $id);
+          return $to_return;
+      }
+    }
+    catch (Exception $e) {
+      watchdog('islandora', 'Failed to purge datastream @dsid from @pid</br>code: @code<br/>message: @msg', array(
+          '@pid' => $this->id,
+          '@dsid' => $id,
+          '@code' => $e->getCode(),
+          '@msg' => $e->getMessage()), WATCHDOG_ERROR);
+      throw $e;
+    }
+  }
 }
 
 class IslandoraRepositoryConnection extends RepositoryConnection {}
@@ -276,8 +324,10 @@ class IslandoraFedoraApiM extends FedoraApiM {
     );
     islandora_alter_datastream($object, $datastream, $context);
     $params = $context['params'];
-    if (isset($params['lastModifiedDate'])) {
-      $params['lastModifiedDate'] = (string) $object[$dsid]->createdDate;
+    // Anything may be altered during the alter_datastream hook invocation so
+    // we need to update our time to the change we know about.
+    if (isset($params['lastModifiedDate']) && $params['lastModifiedDate'] < (string) $object->lastModifiedDate) {
+      $params['lastModifiedDate'] = (string) $object->lastModifiedDate;
     }
     if ($context['block']) {
       throw new Exception('Modify Datastream was blocked.');
@@ -305,55 +355,6 @@ class IslandoraFedoraApiM extends FedoraApiM {
     return parent::modifyObject($pid, $params);
   }
 
-  /**
-   * Purge a datastream from from Fedora.
-   *
-   * @see FedoraApiM::purgeDatastream
-   */
-  public function purgeDatastream($pid, $dsid, $params = array()) {
-    $object = islandora_object_load($pid);
-    $context = array(
-      'action' => 'purge',
-      'purge' => TRUE,
-      'delete' => FALSE,
-      'block' => FALSE,
-    );
-    islandora_alter_datastream($object, $object[$dsid], $context);
-    try {
-      $action = $context['block'] ? 'block' : FALSE;
-      $action = (!$action && $context['delete']) ? 'delete' : $action;
-      $action = !$action ? 'purge' : $action;
-      switch ($action) {
-        case 'block':
-          throw new Exception('Purge Datastream was blocked.');
-
-        case 'delete':
-          $object[$dsid]->state = 'D';
-          return array();
-
-        default:
-          $ret = parent::purgeDatastream($pid, $dsid, $params);
-          // We need to remove this object from the cache and reload it as
-          // Tuque may not have an updated copy. That is the datastream could
-          // still be present within the object even though it's purged out of
-          // Fedora.
-          $tuque = islandora_get_tuque_connection();
-          $tuque->cache->delete($pid);
-          $non_cached_object = islandora_object_load($pid);
-          islandora_invoke_datastream_hooks(ISLANDORA_DATASTREAM_PURGED_HOOK, $non_cached_object->models, $dsid, $non_cached_object, $dsid);
-          return $ret;
-      }
-    }
-    catch (Exception $e) {
-      watchdog('islandora', 'Failed to purge datastream @dsid from @pid</br>code: @code<br/>message: @msg', array(
-          '@pid' => $pid,
-          '@dsid' => $dsid,
-          '@code' => $e->getCode(),
-          '@msg' => $e->getMessage()), WATCHDOG_ERROR);
-      throw $e;
-    }
-  }
-
   /**
    * Purge an object.
    *
diff --git a/islandora.api.php b/islandora.api.php
index 625dd7c5..742c77fd 100644
--- a/islandora.api.php
+++ b/islandora.api.php
@@ -245,7 +245,7 @@ function hook_cmodel_pid_islandora_object_ingested(AbstractObject $object) {
  * modifications, where as manipulating an object's datstreams are not.
  *
  * @param AbstractObject $object
- *   The object that was ingested.
+ *   The object that was modified.
  *
  * @todo We should also include what changes were made in a additional
  *   parameter.
@@ -254,7 +254,7 @@ function hook_islandora_object_modified(AbstractObject $object) {
 }
 
 /**
- * Notify modules that the given object was ingested.
+ * Notify modules that the given object was modified.
  *
  * @see hook_islandora_object_modified()
  */
@@ -361,9 +361,22 @@ function hook_cmodel_pid_islandora_datastream_purged(AbstractObject $object, $ds
  * @param AbstractObject $object
  *   The object to check.
  * @param string $dsid
- *   todo
+ *   A string indicating the datastream for which to get the registry.
+ *
+ * @return array
+ *   An array of associative arrays, each mapping:
+ *   - name: A string containg a human-readable name for the entry.
+ *   - url: A string containing the URL to which to the user will be routed.
  */
 function hook_islandora_edit_datastream_registry($object, $dsid) {
+  $routes = array();
+
+  $routes[] = array(
+    'name' => t('My Awesome Edit Route'),
+    'url' => "go/edit/here/{$object->id}/{$dsid}",
+  );
+
+  return $routes;
 }
 
 /**
diff --git a/islandora.install b/islandora.install
index 12c92009..a2151767 100644
--- a/islandora.install
+++ b/islandora.install
@@ -47,6 +47,13 @@ function islandora_uninstall() {
   $variables = array(
     'islandora_ds_replace_exclude_enforced',
     'islandora_defer_derivatives_on_ingest',
+    'islandora_base_url',
+    'islandora_repository_pid',
+    'islandora_use_datastream_cache_headers',
+    'islandora_show_print_option',
+    'islandora_render_drupal_breadcrumbs',
+    'islandora_namespace_restriction_enforced',
+    'islandora_pids_allowed',
   );
   array_walk($variables, 'variable_del');
 }