Yeah i got standard flywheel too compare it to, they are light but don't reduce the strength of them at all. Some of the most powerful C1J's have used them abd never had a issue with failures or any sort of problem.
Yeah does make it more free reving, i tend to leave crank standard as don't want to loose too much enertia.
Never had one with idling problems though due to flywheel so no worries there