it will effect ur fuel consumption a little bit laa.. not to say it wont affect at all, it will all depend on ur setup and the design of the muffler and bullet.. dont bother bout the FC if u r hunting for power.. ur heavy foot will contribute more effect than the exhaust system..
well, i got a question here....posting on behalf of my fren which is when he accelerate more than 6k of rpm, the left part of his FD is starting to make some sound which is like " proook proook proook " not a loud...