I'd wager that getting specific on cars with known outlier setups is a good idea. They specline specific engines, no reason they would not specline specific chassis, too. So generic strut car gets generic weight, F code civics get this adder (probably as a %), rx8 chassis gets this, and so on. The current recipe of generic weights based on displacement and architecture is cool because you can run anything and not have to bug the rulesmakers to get it approved first. Adding a but wait, there's more... Section handles the outliers cleanly.

Agree with Kirk's assertion about touring vs sports cars not being on equal footing, and I think blurring the old sedan and roadsters lines was a shame given that ramification. Dealing with it by driving out "proper sportscars" Is not likely to happen, so regulations are the best way to rebalance things.