Kirk, you are my hero!
If there is anything I can do to help with this, just say the word.

Now, here's a question: are there any cars classed in IT that COULD benefit from a change in chassis?

I know the 88-91 Civic/CRX won't. The only difference between the chassis is the sun roof, which can be deleted legally anyway.
I think that in order to make a request for change bullet-proof, someone (some many) would have to look at all the vehicles classified and see if there is any that may have a different trim chassis that would give them an advantage if swapped (chassis bracing, slightly different suspension geometry, etc.)

??? or am I off in the weeds?