Template with Dropdowns needed for product selections

Newbie here using 1.3.9f. How should I setup 3 levels of product resolution for my site? For example:

1. Car manufacturer - selections (Ford, GMC, Chevy, VW, Audi)
2. Part description - selections (master cylinder, alternator, steering pump)
3. All part numbers matching the answers selected in 1 and 2 above in a drop down menu.
   Is there a limit to how many categories or product types you can have? My 1st question (categories) above has about 30 entries and my 2nd question (product types) has only about 6. Is it possible to have dropdown lists for question3? The dropdown lists will have a hundred or so possible entries in each.

Since I could swap the items in 1 & 2? Are there limits for either?

Any help is appreciated.

What you are describing is dependant attibutes
First select make, then model, then year etc
Display only those that are pertinent

Unfortunately, ZenCart does not have this functionality built in and I have not seen any opensource package that does...

There are several commercial, auto specific, soliutions that do but are in the $5,000 to $10,000 and higher range

...Sucks huh, I just have ALOT of duplication. But my site only has 16 vehicles EVER made, with 10 subcatagories each......someone should make an add-on:D

.someone should make an add-on
It is quite complicated and why the commercial opyions are expensive

kobra:

It is quite complicated and why the commercial opyions are expensive

not really... http://vehiclefits.com has a free version for Magento.. Magento seems to have all the cool things that Zen Cart doesn't. Like a search box that returns relevant results.

someone should make an add-on

Someone did:

http://www.zen-cart.com/forum/showthread.php?t=161143

YES, FINALLY!, This is going on tonight!