Sometimes you just can't tell how something is going to look. I have 20" American Racing "Palmettos" on a stock Windveil Blue GT premium, automatic. It is the perfect daily driver, it is import looking yet retro, extemely shiny, not too blingy.... but looks really rich, as in quality auto, the guys at the Lexus dealer drool over my Mustang. No it definitly takes away some of the muscle car look, but anyone who cares knows whats under the hood, every modified mustang on the road wants to take me on, must not be too blingy!
(Celticstanger your car is cool, like the wheels, and it does look muscle)
It does compromise the true performance....but for those who want to just kick around and play a bit with the power it is actually more fun to drive becaue you can feel the road, and hop around corners (not sure you can keep from hopping around corners), but that is on an automatic that hesitates slightly before the jet engine kicks in, those twentys could get annoying on a manual, don't know.
I bought a manual 5 speed just because i realized mine was fun but I was missing something. I'm definitly going with 18s in this car, 18x8.5 up front and 18x9.5 in the back.