I would concur with ghost. It's probably the second best upgrade I've done. I gained about 3mph top end "kept my pipe long" but noticed a significant low end increase. Before I needed to pedal up to about 5mph so the engine wouldn't bog on my 50cc, it's down to around 3mph now. I can actually take off from a stop, but prefer to pedal up a little. Acceleration is much quicker. I don't think the pipe is much loader then the stock, but it has a much more noticeable sound. It just sounds more like a 2 stroke bike now, so it attracts more attention. The stock muffler I always thought people turn to look because they wonder why that lawn mower is getting closer.