depends on what you want to do with the bike. if it's just to clean up the fuelling with the new pipe the Power commander is the quickest and easiest way. you can fit it and just drop one of Dynojet maps in there. with a flash you can do a lot more depending on what bike you have. I do both, but I find that power commander is the best way to build fuel maps, so I can save the customer a lot of dyno time by using a power commander. so to make it easy power commander will only do your fuel map, where if you want more a flash will let you
