I did a 3.89 gear change, an aluminum flywheel, and a SCT tune all at the same time on my '05 GT 5 speed. I also raised the idle RPM to 1000 to quicken the engine accel at the touch of the throttle. The engine does accel/decel much quicker. And, the RPM falls quicker between shifts - no more RPM hangup going up to the next gear.
I am VERY satisfied with the performance improvement but the factory tires are hating it - tire spin on demand in the first 2 gears.
I am VERY satisfied with the performance improvement but the factory tires are hating it - tire spin on demand in the first 2 gears.