After buying my 2011 yz450 I began researching what exhaust worked best on the bike. Everywhere I looked they raved about the Yosh and its massive power increase across the board. I decided to order the slip on and find out for myself before I went and bought the full system. Once installed and remapped the EFI the bike pulls longer in every gear, comes out of corners quicker looks great and sounds awesome without being too loud. I am very happy with my choice and recommend this pipe if you want to get those extra ponies.