Those are definitely more rare-ish than rare. I see a Supra almost every trip to the used cars. Is it the Renault 5 Rally you're trading or just the street version? If it's the rally car then you have something very rare as I haven't come across one yet.
Which supra do you see? i see SZ-R all the time but not the RZ, an it is the street version 5 turbo, i seen a renault maxi turbo the other day in UCD didn't have enough money tho