To really get the full potential out of the pipe you need to open up the air filter. That is your main point of restriction now! I have a Techingas on my Vento with the stock airbox and no re-jetting. I can't really speak from experience, it didn't have any exhaust before, but it's definitely not a screamer like my ZX! I also haven't done any plug chops on it either, so just the pipe may require a larger jet. I haven't had much time to work it. Dre, at this point you probably need to do a plug chop and see where your mix at. If you plan on getting an air filter, now is the time to do it to save a little time on tuning. With the air filter you will have to re-jet again and more plug chops. The key is not to run lean!