I have to admit I don't see a lot point to those cars at least here in USA because we've got the buggy-based platforms to act as a " onroad GT" class and we've got the traditional 1/8th onroad platforms as well.
Those chassis's in the link blur the distinctions between an onroad GT class and the 1/8th onroad class. If they were allowed to race against GT's, you'd next get people just putting a sedan body on an Evolva or MRX-4 and calling it a GT.
Interesting nonetheless!