On the aluminum flywheel, I noticed how much quicker my engine revved, it was very noticeable, especially in first gear. That said, as the others have stated, they also make the car easier to stall, and harder to smoothly engage the clutch. My car is on the lighter side, and 3.73 gears also help, but the car was more user friendly with a steel flywheel. Stroking the engine has since helped, since that increased the rotational mass, helping to make up for the lighter flywheel. I'd probably still go with the aluminum flywheel, but it's not for everyone. I personally didn't notice a difference from the aluminum drive shaft, in any direction, I did it solely to lose weight, which it does do.