I have a tomos that has about the same speed. I have heard you can get the exhaust port honed to a bigger size to further increase flow and if the stock pipe has a removable baffle in it, you can take that out. It will be a bit louder but probably not much. I am trying to think of a way to make a forced air cowl that goes to my carb, i think at the higher speeds the air will be forced into the carb, increasing the amount of carburetion going on, basically making it go faster. But i don't know how much speed would be gained in that, since it's a moped not a sports car. But that is a very cool concept. they have made speed kits, soon they should start to make intake blowers for mopeds.
swarm 'n' dstroy