And you can use the filter controls at the top of the page to get as close as possible to your vehicle. We don't track engine displacement or trim levels, so you might need to do some of your own filtering by looking at vehicle names and descriptions a bit. Here's more info about the level of detail we track: Why don't you track more vehicle details?
I think that you've hit the nail on the head, pb. This is an ever-expanding tradeoff of including more information to enrich the data included at the expense of making it harder to enter that data. On the one hand, more meaningful data can be marvelous to capture, but on the other, it turns off less savvy users that help to provide the basis for the data in the first place. This is something I deal with on a daily basis at my job (meaningful enrichment of user supplied data), so I can certainly understand the issues.
Providing this kind of information after the user has entered their vehicle (from the "EDIT CAR" dashboard, for example) might at least let those that are a bit more savvy about their car include that information, without confusing/cluttering the initial addition of vehicles.
UI development is certainly a fine balance between usability and complexity. I've found in my work that simple >> complex almost universally. Sure it may cause some of the more technically inclined irritation (lack of "options"), but in general, I've found that making things simple is always better.