Originally Posted by Takumi Fujiwara
"Killing of the motor when going from high RPMs to idle" is not related to going to a lighter flywheel. You have a problem somewhere else.
Anyway... I chose to go with a 12.5lbs flywheel, but now I wish I went lighter. I couldn't tell much of a difference off the line, but when it starts to rev, you'll love it it revs faster and faster to redline. When you're matching revs while downshifting, you'll love how much faster the rpms come up too...
It will kill the motor when coming down from high rpm as there is less weight to slow down. The computer doesn't react fast enough to change the fuel to regain idle.