If you're asking if wheels with 185/65R14 tires on them will fit your car, you need to know more information - your car originally had 14" wheels, so diameter is not an issue. What you need to know is the spacing of the bolt-holes in the wheel; for an MR2 there should be four, 100mm apart. That's referred to as a bolt pattern of 4x100. The other measurement you need is offset. Wheels for our cars have a high positive offset, that is, the face that mounts to the hub is close to the outside of the wheel, rather than closer to the center.
If you just wanted to know if 185/65R14 tires will fit on your car...
As Nick said, 185/65R14 is very slightly taller than 185/60R14, shouldn't have too serious an effect on performance, and you actually might see an improvement in fuel mileage. If you're getting used tires for cheap or some such, go for it.