Not really....
Adding just slip-ons with stock head pipe would be 'ok'.... Good for the bike? no..... Harleys run naturally lean from the factory. A full system I would not do without a tuner/AC since it will eliminate the cat and dramatically increase flow. Once you free up the exhaust decreasing back pressure, you need more air and fuel to richen things up. A lean running engine will run hot... hotter than it should which is never good. So now you need to get more air and fuel... hi flow AC will get you the air. But then you are stuck with hi flow IN the engine and hi flow OUT.. and you now NEED to increase fuel flow, spark advance etc... to get the air/fuel ratio correct for the new intake and exhaust. That is when you get a tuner to dial it all in. No one ever said it was cheap... that would be a lie.
Ever see a bike with pipes that are 'bluing'? Sometimes you see it right in the middle of a muffler... or near the header pipe collector ( not talking near the engine for this )... that is a tell-tale sign of a lean running bike... the discoloration is from the lean condition and the heat it causes.