Hello mate, On my 07 GSA I have Remus Headers, Remus Hexacone Silencer, K&N air filter but I also use a power Commander to richen things up as I feel it would run far to lean, not checked on rolling road yet, but rather run to rich for now than to lean.
The bike seems a lot smoother for the addition of the power commander, not shaw the K & N air filter makes much odds, will have to get it all set up by an expert.
No doubt some one with better knowledge may give you more info