There is way more money in the basics like fluid changes,sprockets,chains,plugs,valve adjustment,tps sync and things of that nature than in the heavy performance stuff.Most guys make much more on tire changes than the actual tire because you have to sell so cheap to stay competitive.Most guys want the fender eliminators,integrated taillights and hid and there can be some good quick cash in those jobs.But just a friendly opinion from a guy that has built some heavy hitter big bore,nitrous and turbo bikes,be careful what you jump into if your somewhat new to bikes with a power adder,they are not the same as cars(similiar but not the same) and blowing things up gets expensive quick.It's hard to hurt a bike with a pipe and pc even if the tune is a little off but throw a little spray or boost in there and its easy to wax a very expensive motor.The best investment you can make is a quality lift,saves so much time and makes jobs much easier.