did anyone knows how to implement a Year / Make / Model Product search for Joomla / VirtueMart?
There is no easy way to do this. Depending on what you are trying to accomplish - tag parts with the y/m/m that it fits vs. listing cars by y/m/m it goes from hard to harder. The current version of Virtuemart is a poor component to start with when trying to extend the functionality since it is not MVC and it is not designed to be extended.
The easiest way would probably be to write a new component with 2 tables. One with the y/m/m info and the other that maps VM product IDs to the y/m/m that you want the product to show up for. That would avoid hacking the VM core files so you could still update, but it would be a pain for administration.
Another option would be to use K2Mart so you can use K2's extra fields. This would be a good solution if each product has a single y/m/m. If each product can have multiple associations it gets a little tougher but it could still be done. You could also write a K2 admin plugin to handle the y/m/m duties.
If you want to give more details on how you need it to work I can probably get you pointed in the right direction, but any solution is going to be a pretty significant amount of code and database work.