I would love to see a wide variety of custom body kits, spoilers,wheels and other things to truly make the custom variants of cars unique. A great example of vehicle customization is NFS Underground 2, you could make what seemed like an infinite amount of unique looking vehicles.
To be honest "ricing" is something that I could wait to see in this game, I'd much rather prefer more engines. Make them for different kinds of layouts for your vehicle, like maybe some built for speed and some that dont go for speed but rather torque and pulling power for carrying heavy objects and trailing trailers. Customizable wheels would be dandy I'll admit though.
