Put a stock exhaust back on it. There are books covering the complete assembly, disassembly, repair, maintenance, troubleshooting and upkeep of the entire bike (including the exhaust system). All parts, techniques and procedures have been authorized by the creators of the motorcycle to be the official instructions.
If you’re going to outdo the Buell engineers and want to do it on your own, I highly recommend checking out the curriculum at your local community college or enrolling in a motorcycle oriented vocational school such as MMI. However the factory exhaust was designed with the best compromise of low noise with maximum power, lifespan and reasonable cost.