[speeder]

I ride an old BMW airhead boxer and honestly, it's pretty smooth in the rev ranges where it lives. The redline is ~7k and it only hits that going through the gears once in a while. I'd personally concentrate on getting the tune balanced as well as humanly possible and maybe micro-balancing the reciprocating components.

Don't get me wrong, those are beautiful parts but I don't think that you will get a noticeable difference in feeling or performance from them.