So, what do you guys have in mind specifically? I don't think we need to max out the engines or cars - so 601 hp from a charger might not be necessary, but who knows?
Let's all do some research tonight and see if we can come up with specific ideas that would work - find one or two cars that work together and are pretty even. Then jot down exactly what you did to each car and that will be your idea for a series - any changes can only be made if everyone agrees (like we did with the Minis and the LSD).
Heck, here's an idea. We pick a model year of the Evo and STi (or STI now) that is very close and specify that model everyone use either one or the other. It will be an exact car, so there will not be two different STIs or Evos on the same track. Then, we do the SAME race compound tires (for example, the first tire selection), the highest level suspension, highest level weight reduction, and the first brake upgrade; open up the track, and let them go at it. They're already pretty even in HP, and they have plenty of it, so engine upgrades will not be necessary (or allowed).