It'd be hard to get anything to stretch over a 7j to be honest. A 185 has a small "bend" but nothing to special, and on an MR2 i think a 185 is a bit small? Ive only seen 185's in 14" or less too...
I know of some proper bo rims for sale, 8j (i think) front, 9.5j rear with tyres if youre interested and have coilovers (wont fit up front without coil overs)..
Paz