If your goal is to make a little more power without making alot of noise then a stock E header or a aftermarket E header is a good choice. It will add more power then a slip-on. You will need to mod the mid pipe(expand it) so it fits on the larger diameter header. As far as jetting, that would depend on where your jetting is now. Have you done the 3x3 mod and rejet the stock carb? Do you have a FCR? Stock jetting is already lean so the E header would require richer jetting. But if you already rejetted, you may not need to change it again. It depends on where your jetting sits currently. Hard to know for sure until you try.