I have an 2010 ISF with full bolt ons, except headers. The car is an absolute beast, I switch between the F and the f30, and I can say that it feels like the f30 has low end torque and the F has high end torque. Driving in the city with the f30 is fun cause throttle response and after the jb tune, its just a monster going from like 20-60, but once you pass like 4k rpm the car doesn't seem to pull that hard, but the F starts to really open up at 4k rpm and starts pulling hard I drove to Santa Barbara this past weekend averaging 80-100 and I averaged 26 mpg which is pretty good for a 5.0 v8, but when I drive in the city I average about 15, LOL. Got a heavy foot (cause the exhaust
) The ISF is def a head turner though! Oh yeah, and I haven't had a single problem or people on the F forums don't seem to have any major problems up to 100k.