You might want to specify that in the specs, then. My understanding was that I was required to race level upgrades on platform and handling. Obviously, I understand how difficult it is to set specs for a garage. My preference has been to not set a restriction I can't set in the game. Might be easier to just leave the Z/28 out of the list, I don't know. Still, very solid concept! It really is grassroots in that you have to manage the weight with your driving rather than stripping out the 8-track...do you remember those?
Edit: I just read your PM...that sounds like a plan.
DD