If you not done anything else to the trike but the pending exhaust, most of the experts says the stock ECM will compensate for the better flow. If you also change the air cleaner then you will need to think about some type of tune or things will get way to lean in the fuel mix. You might consider the tuner anyway now because it will help out the stock factory lean mixture. By adding some fuel the bike will run some what cooler. That's just the highlight on the subject it is very complicated and opinionated.Thank you Gorilla !!!