oh, i agree that the engine can probably handly much more than 75cc. but i am mostly concerned w/ the brakes and frame holding together.
but i've known too many people who have gotten speed kits and then ran into problems. sure, it was often their fault. after all, people often don't want to wait for the breaking in period when they just got their speed kit.
but i'm also opposed to speed kits for abstract reasons. i like that mopeds go fairly slow. i don't think i'd want to go much faster. if i really did, i guess i'd buy a motorcycle.