i used to do something like this back when i played grand theft auto for the pc, except it was only top down views which are much easier. you would shade and detail the whole car and all that, and import it into the game. shading and all that, kinda fun.
No car anymore ;\ (taking a break from driving due to several misfortunate occurances)
Newest mod for my Dad's Cobra 'vert: My beautiful girlfriend and I for passengers when we want to go somewhere