Don't know the material of a stock flywheel, but if it's cast iron then eyeball it close for heat cracks. If they're light and not deep resurface flywheel. Don't know about these smaller motors but on good hp producing American V-8s I have seen more than one flywheel explode from cracks. Cast iron is a crappy material to use for a performance flywheel. Heat cracks also can lead very easily to clutch chatter at engagement. Lighter is better on small displacement engines when it comes to flywheel, but you may be forced to relearn somewhat your off-idle driving technique. You have to be less aggressive releasing the clutch, less inertia there to yank car away from standing still.