Why is changing out the motorcycle exhaust the first thing most people do when getting a bike?
I think for two reasons one is that usually the sound on a motorcycle is unique to how the owner of the bike prefers it and second a stock motorcycle exhaust is way heavier and as well as the restrictions in the stock cans restricts the power of the bike. You can generally drop an easy 15 to 20lbs of the total weight of your ride just by removing the stock muffler.
These days removing the stock motorcycle exhaust for an aftermarket is usually fairly easy. The one problem is that most bikes now are fuel injected and therefore will need to be re mapped in order to run properly. This at least seems to be the case even more so for sport bikes then cruisers. However either way when you are considering this mod make sure you allow for having to have someone re map the computer on your bike. Other than this just doing slip ons which basically just replaces the stock motorcycle muffler with the aftermarket, this is easily enough done in your own garage if you feel like doing it yourself.
Usually installing a motorcycle exhaust and remapping your bikes computer should not run you more than about $150. Now if you are doing a full race exhaust on a motorcycle it will run more due to the increase in labor.
I don’t think I have ever owned a bike that I did not do this one as the first thing to make it more my own.