big guy checking in. 5'11" 230lbs. So yes, i could lose weight, but i mainly switched mine to the delkevic slip on for added awareness of other drivers, and to get rid of the vacuum of a muffler that is the stock pipe. Wasn't really gunning for performance, if that was the case i wouldn't have bought a 250cc thumper. But i love this bike, and the unintentional (to my methodology) consequence of the slip on is that my bike felt a little more peppy and rev happy in the higher ranges, with no ill effects of backfiring (although my name would suggest otherwise) or running lean. just my 2 cents.