A couple of things you need to consider about that 30mm pumper. The carb will fit to the motor fine with a 30mm intake but will it fit in the swingarm frame? The 30m intake sits at a slightly higher angle than the stock so you may find a crossbar blocking the inlet. In a yerf and a dazon we had to omit the heat spacer and bolt the intake directly to the head to barely get enough clearance for a velocity tube and air filter. It's tight! The external pumper circut also hits the passenger side motor mount so the carb has to sit at a slight angle. The carb works great after you adjust the float level to account for the slight angle. The stock throttle cable has to be re routed at a different position too so you may find you will need a longer cable.
That carb flows 20% more air volume so if the stock exhaust can't flow accordingly then you won't feel any real benifit from the 30mm carb other than maybe a little better response when stepping on the gas. it's not good when you have too much air going in but it can't get out. you may find your loosing power at higher rpms. The 30mm realy gives a nice punch but figure on upgrading the exhaust as well.
$260.00 is preety steep for this carb. I am using three of these and they work great
http://cgi.ebay.com/ebaymotors/30MM-...item588f7a43d1