Maybe if you're running Nurburgring everyday you could benefit from the lightweight flywheel.
until then stick with the heavier. the lightwgt is too light and has tons of clutch shutter in daily driving. and no real benefits of holding rpms between shifts that i noticed.
also you have to think about how heavy the car is, by reducing the rotating mass(by going LW flywheel) you're going to hinder yourself in low end torque. thus more rpms will be required to move the car from the start. i had to start at about 2k RPM from a stop just to avoid clutch shutter. i went back to steel and ill never go lightweight again.
K&N CAI, lightly ported stock TB/INT, JBA Hpipe, Spintech Side Exh. (13.1@106 r/t .8800 60' 2.06)
1/13/10- Kooks 1 3/4, LS7 Clutch, B&M shifter
1/21/11 - Eibach Springs, Monroe Shocks, EBC Brakes
Soon - "Sungold" PowderCoated 17"s