It might be nice to be able to filter based on year of the vehicle. The reason I say this is that models don't always stay the same over the lifetime of a car or motorcycle. For example, the 2007 and older Kawasaki 250 Ninja is drastically different than the 2008 and newer. For cars look at the Corvette or perhaps the VW Beetle.
A start and end date could let you do comparisons based on generation (1968-1982 for 3rd gen Corvette). Motorcycles have generations as well but there is currently no sorting on the motorcycle section.
You can filter motorcycle by year right now. Just click the year on a model listing page to see only vehicles in that year. For example, here's the page for 2007 Kawasaki Ninja 250R. Notice that the URL for that page has a year at the end, so you can go to any year for that particular model by changing the year in the URL if you don't want to click from the model page.