sounds like another import comparison so i will stick to imports and not get into domestics. here is a list of cars that i think compete with supra's and rx7's in any category that are JDM.
-300zxTT
-3000gt vr4
thats all i can think of stock, used, import, and offered to the US.
BTW: for the price of the supra you might be able to consider spending a little more and getting yourself a STI, EVO, 350z, s2000, and used NSX's.