I'm still thinking of getting one. However, my friend has caused me to think some more and I need to ask you guys what you think. He was telling me it's more popular for N/A cars than turbos and he dosn't know if it's a good mod with a turbo. I'm just double checking because I really don't want things to break on me again. Lighter flywheel won't hurt right?
a lighter flywheel is fine for a turbo car, it while help the turbo someone a little faster and accelerate better. but you don't want something like a 9lb aluminum flywheel because it will probably end up costing you problems. i would recommend a 13-14lb chromoly steel flywheel. i know cobbtuning.com sells the ACT flywheel for your car.
I had a 12.9 pound flywheel on my legacy (stock was 28) and i hated it. It was not very friendly on steep hills and rattled/screamed a lot on deceleration. I got misfire codes from the ECU, i am told, because it spins very freely and decelerates too fast. I went with an old 2.5 RS flywheel which is about 16-18 pounds and love it. Very driveable, cheap, and it revs faster which was my initial goal. I believe there was a recall for your year WRX that put in a heavier flywheel to solve misfire codes (don't quote me on that one) so going too light could indeed cause problems with CELs and drivability. I would find someone with a flywheel of the weight you think you like and drive it around for 20 min. You'll see right away if it's something you want to mess with. Sorry if i sound very downer about flywheels but i've played the game and gone too lite and hated driving the car in stop and go on hills (285/85 interchange anyone?). Just want you to be sure you want this with potential downsides noted.
get stage 1 flywheel, & clutch.. u will be fine for the horse power u want which i'm guessing below 300 whp or 250 whp.. around