Stock bike with a filter, no porting in your future, Toomey T-5's. Stock bike with definite porting/polishing plans in the not so distant future, CPI's. I have a stock shee with T-5's, V-Force and a cool head and it hauls ass. The bike listed below with the porting, carbs and increased compression, among other things, needed the CPI's and its just crazy fast. Pro Circuit makes a very nice pipe as well, more of an all around pipe and is very reasonably priced when compared to the aforementioned pipes. Remember, ANY pipe you choose will be a huge improvement over stock, you just have to decide where you prefer the power.