Affect economy and performance........
My old 600 did 120 ish. 170miles to a tank and ran ok.
Proffesionally fitted dynojet kit, full system, k+n etc and it did 150mph and 110 miles per tank and went like sh off a stick.
Fitted well by someone who knows how, ideally on a dyno like mine was and it will be superb as the bike will make the performance it was ment to without compromise on economy and noise etc.
Done diy? Throw a die and keep em crossed.