This all depends on your cost targets, but going to a chain drive will also remove some additional weight, and you could then get the lighter wheels as well. The chain drive will also get you a few more ponies to boot. I've removed some extra tabs here and there on my drag bike. Take off the inner rear fender liner. COPs instead of the stock coils. Take off the mirrors, turn signals, get different foot pegs, lighter tires, remove some of the rubber guards over the top of the engine, go to a dry cell battery, remove one front rotor and caliper, different exhaust as mentioned earlier, cut down seat, remove passenger pegs.... and I'm sure there is much more. It all adds up, but you aren't going to find too much without spending some $$. Best bang for the buck for me would probably be wheels/tires and then the chaindrive conversion. The most weight the bike can loose usually comes from the rider.... that is my biggest problem right now.