Код получения только InStock продуктов в product_collection
$collection = Mage::getResourceModel('catalog/product_collection'); $collection->setVisibility(Mage::getSingleton('catalog/product_visibility')->getVisibleInCatalogIds())->addFieldToFilter('status', Mage_Catalog_Model_Product_Status::STATUS_ENABLED); Mage::getSingleton('cataloginventory/stock')->addInStockFilterToCollection($collection);