vehicle to autoparts relationships

I have a challenge, to figure out what part of the vehicle to relate parts to. I can't relate a part to the entire vehicle. Why? Well, a vehicle can have, apparently, more than one engine configuration. For example, I have a Honda Civic with a 1.5L engine, and it can come with a 1.6L engine as well. Now, I don't know that much about auto mechanics, but my understanding is that you can have some similar parts for those two engines, and some different parts. Thus, I believe I need to relate the parts to the engine configuration. However, that's only for engine parts. There are also transmission parts. The car can come in manual or automatic, so now you have different parts that relate to the transmission on this particular vehicle. Going further (and getting funner), your wheel base affects the parts you have, and then there's the body style. Thus, you need to relate the part to the particular application, not just the vehicle.

All this to ask if my thinking is correct: is it best to create an Xref table between each autopart category (engine, transmission, exhaust, body, etc) and the parts table, or one large xref table between the two, with the addition of a category field. The one large xref table would have it's foreign key related to each of the tables that govern their group (e.g.: tbl_engine.engine_id, tbl_transmission.transmission_id, etc)