I installed my Leo Vince slip-on muffler (that I bought for my Honda CB500F) on my Kawasaki Z250. And although I love the look and the sound (not sure what the rest of the mubaan thinks of it) but I have the feeling that I did lose power in the low-end. Am I crazy or could I be right? This morning I did put back the stock muffler and my feelings seem to be confirmed. Later today I will try the Leo Vince muffler again on the same stretch of road and see if I really notice a difference or if it is just a feeling.