I don't think I'd worry about the flywheel.Getting the crank welded is a good idea.Banshee is right,you can get a cheaper port job.Don't let them talk you into a drag porting,if that's not what you plan on doing with it.Just a good port job will do wonders.20 cc domes would do just fine.Who ever you buy the head from,ask what they would suggest.Make up your mind what exactly you want to do with the bike(trails,drags,all around bike).Don't let them talk you into something you don't want.