Like the guys said, dyno tune is best. I have a flashed ECU and a PCV dyno tuned. If I understand correctly, you are worried about having to go back for a retune every time you make a change, but why not wait until you get all your upgrades installed and then get it tuned. Is not like the engine is going to fail due to, for example, an exhaust system without a tune. A lot of guys on the forum have ran an aftermarket exhaust without a tune, myself included. Good luck on making your bike the way you want it.