After dealing with a tiny gearing change (47 rearsproket) that I'll say "I'm happy with" just to justify, losing 10lbs of weight (on me, not the bike) would give it more get-up-and-go.
If you want to go full-bore street or full-bore dirt you'll feel the difference. Something in the middle... they pretty much come stock that way.
Adding up most of the bolt-on accessories I've done most are for comfort. For better performance I bought a 250. Tweak-away.