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..
i'm currently using Federal RS which has the 180 treadwear similar to Advan AD07 tires and pretty happy with em for Circuit track and Hillclimb rally use and have been...