In a similar situation, when you purchase a new Harley and go stage 1, which is a free flow AC and exhaust, a re-map is usually performed. But because of the popularity of the Harley, just about any dealership or indy can dyno and tune for the new parts.
Granted LOTS of people just purchase the new exhaust and AC and run as is and are probably not going to do any damage.
But for the best performance, it's best to re-map the ECM. Without it you may get a bit of decel popping in the exhaust.
Even a stock Harley can benefit from a dyno tune to get out of the extreme lean running to meet the EPA standards here in the US.
