I have an aluminum flywheel in my mustang, and I don't like it for street driving at all. It shudders at stop lights and has no pull off the line. Wind it up and it spins up much quicker though. I wouldn't run one for street. Only for road racing/ autocrossing type stuff. Drag racers use heavy flywheels, and a heavier one smooths out your motor and decreases rpm drops between shifts.

"The first rule of overkill: You can never have too much overkill."
"Overkill is underrated."