Two super easy resolutions:
1) Just post it in a sticky.
2) Add an optional VIN field to the Garage feature. One issue with this is how is the data preserved when the car changes owners? Could be difficult if you wanted to separate "car profile" from owner info, although it might be a kind of cool feature?
Of course, you could have a VIN field in the Garage, that ALSO populated an archive that didn't store personally identifying info but just relevant car info such as year, color, etc. Or that automatically posted to a particular forum thread.
J