Thanks for the answers..

I am thinking of ITE in a class for, as you said, bring what you got as long as it does not fit in one of our established classes.
Since posting I have been reading a lot about the different region's IT (E,X,E-O,E-U,etc) classes.

Seems like some are more into the ex-firehawk, escort, etc classes and rules, others to fit random cars.

I see it as a way to allow cars to compete without excluding, be it for as long as the SCCA certifies them, till they change what is not legal, or forever on the class.

Our case (and yes it's Puerto Rico) we are not SCCA, but we follow the SCCA GCR, but as any other place there are cars that do not "fit"
We do not have STU/STL (which would allow most of our GT3 cars) so we are looking (I am looking) for a decent option to propose to the Club.
We do not have the luxury to turn away possible racers because of purism.