That would be a bit less effort if we can have insim packets for this. The best is to have ability to send an insim packet, which has minimum and maximum setting for each value of car setup for each driver (say, we send it when driver connects). That would be the most flexible way possible: you can make special championships when people can choose what to improve in the car, and also we can have custom cars that way, etc. Also it would be nice to have sliders in insim
And basically it would be at least around 132 (setup file size) * 2 + 4 (header size) == 272 bytes size, which is already bigger than 256. That will require some (not too hard tbh) magic in insim format, since currently every packet has only 1 byte for size, so max size is 256.
Anyway, that does require a lot of work, and for those who really need such functionality, they could just RIP the set on the fly and spectate people if setup doesn't conform.