R31's, R30's,Ae86's?

I think you may need to widen your search globaly as they are very sought after everywere.

There is a Guy/Garage turn left off salwa road, heading from doha, at the Merc building.

You'll see some retro American cars from the 60's and 70's he has for sale. If he is as I suspect importing them.
He may be able to assist you in tracking down a dori wagon:D

And as for the question of Wankels in this climate, I think air temp causes a bigger problem for Turbo'd cars as they would suffer considerable performance loss during the summer due to High air temps.