The YMM contribution store data in cookies so if the customer selected BMW MX3 it will be already selected for him next visit time. The make/model/year dropdows in the "Select Vehicle" box are dependent. They show only the makes/models/years that you store have products for. After the make/model/year were selected the "Categories" box will be filtered. Only the categories that have products for the selected year/make/model will be shown. Download the contribution and view the screenshots to better understand what it is. There is a sence in creating an "all products" page and show it filtered just after the customer selected year/make/model . But I don't think that everyone will like it. So I have left the instructions in the README.html how to make any custom page filtered by year/make/model. This package contains autoinstaller script. It automatically install the contribution: copy files, edit files, alter database tables. It saves a backup before any action and make possible to uninstall the contribution. You will need to do manually only what the script cannot. It was tested on host (PHP:5.2.4 MySQL 5.0.67) and osCommerce Online Merchant v2.2 RC2a