you wont gain any power, it reduces rotating mass. makes you rev faster.. so you'll notice that you do go through the rpm range quicker. it's a nice mod if you ask me. i loved it on my lx!
crank is internally balanced. and the flywheel comes balanced too. but you can take it to a machine shop and have everything balanced if you're worried about it.
My lightweight flywheel doesnt change its idle at all, perhaps ur ect is faulty. I blieve theres a slotted set screw on the throttle body you could play with see if that helps.
