I've had the re-flash done. The only other mod is a Delkivic can, which makes very little difference other than looking and sounding better, and saving 14 lbs of weight over the stock muffler.
The low-end (2K to 4K) power is definitely better, but if you are looking for a gigantic difference, you'll be disappointed. Yes, it pulls harder at those low revs, but not OhMyGoshMyArmsArePullingOutOfTheirSockets harder. It's like going from an 1200cc bike to a 1400cc bike. Above 5K, I'm not sure if there is any difference at all according to my butt-dyno.