How do we handle poorly-delineated models (e.g. Impreza, Impreza WRX, Impreza WRX STi, STi), and what about badge-engineered vehicles?
As a Saab 9-2X owner, I'd like to be able to see my fellow 9-2Xen lumped in with the Imprezas that we properly are. Upon digging around, I've noticed that there are lots of WRXes in the "regular" Impreza group, too. I read back through the Jetta TDI thread, and filtering by engine type makes a pretty convincing case for combining models - so what of the WRX? And what about when a car maker decides that a special trim line is now its own model (e.g. Neon vs SRT-4, Impreza vs STi)?
Further, what about badge-engineered cars like the Toyota Matrix/Pontiac Vibe, Geo Prizm/Toyota Corolla, etc?
nah, we're not going to lump them together. Even if the cars are very, very similar, we consider them different vehicles. It's fairly easy to browse through a couple different pages to see mileage, so I don't think it's worth confusing people by not following the manufacturer's name for vehicles.
We automate the site as much as possible and our data model won't allow us to combine cars from various manufacturers like you're suggesting. With user-submitted models we get mistakes from time to time. The Jetta TDI model issue was a mistake that we corrected, only the engine was different. The car was by VW and it was called a Jetta. I think it makes sense to have them together.