I can't resist...just replaced a zetec motor because it swallowed a 5/16th flat washer (don't ask, I have no idea how, when or where). I think the motor was original, never out of the car since 2003 with 8000 miles (?) and still ran just fine.
Classes- I second Mr. Green: Open wheel-FV, FF, FC, FA (and maybe some form of FB) and no more than 15 clases total on the national level. Each of those classes should be distinct and identifyable. I don't like spec classes, but thats a personal opinion and I agree that there should be at least one per car type (open wheel, sports racer, production). Keep it simple and attractive to new blood (just look at the growth of NASA in a few short years).
I might add...the classes should not be stagnant- new technology is not a bad thing and the classes should embrace, not run from it. eg; alu brake calipers or a 5 speed sequential box in FF/FC if that's what the rest of the world is using. A little thinking outside the box is always good