2 1/4 especially with those headers is completley a waste. With a 2 1/2 exhaust you will pick up 25-30 horses combined with the headers as well as a ton of torque. Remember to think of an engine as an air pump, you have all the right stuff getting the air in, but your blowing it out through straws which is gonna hurt you a ton on power. You don't have to spend $500 on a 2 1/4 inch exaust, you can get a bolt on setup mandrel bent from summit for $209. Its not stainless but its a diecent setup!