I think a weight limit is in order, to ensure an equal racing condition to those that race the FWD class.
The upside to FWD in USGT is that one would hope that this would either increase participants eager to get there preexisting cars into the mix and have some fun! Even if they do not post the lap times, and have similar handling, it would make for some good racing ala' the 24hrs of Le Mans, when multiple classes are on the track at one time. I too am the mindset that they should run FWD bodies and not the current Open GT style bodies.
Be sweet to see some DTM , Open GT, and Fwd cars mixing it up!