Big brakes, wheels and tires with almost even tire size (width) from front to back. Upgraded handling, possibly lowered a bit. Lots of power and a lot of guys go the centrifugal supercharging route with fuel injection. Comfy seats and a highway rear gear. Clean exterior styling. Here's an example of a Charger done in the protouring style:
http://www.lateral-g.net/members/musto/
Did I miss anything? Let me know.