Having an ECU flash done on the GEN3 will not do much...if anything. The biggest reason to do one on the GEN4 was because the U.S. models were very restricted on emissions and sound level, that it took away almost 15-20 horse power on the top end of the RPM range. So people have their GEN4 ECUs reflashed to remove those restrictions. The only reason to have GEN3 reflashed would be to raise or lower your current redline or take away the top speed restriction of 189mph set by the U.S. Some people who race and have a built up motor might want their ECU redline increased or top speed limiter removed. I wouldnt risk blowing a motor though...just my two cents.
However, if you really want to get the flash anyways, you can simply remove your ECU and mail it to a company for a flash, with insurance to cover the cost of the ECU if it gets lost or broken. You do not need to buy a new ECU or get a powercommander. If I had to chose one or the other because of cost I would get the power commander and custom dyno map. This would increase power slighty on your bike if it is stock, but more importantly...like you said you wanted, it would smooth the power band out...if the dyno tech is good that is. If you have an aftermarket exhaust, especially a full one, or...you removed you cats from the headers...I would definitely get a power commander.

 

If u gut cats u have to reflash ? Or check engine light will be on right. Can u still ride fine with that on

 

Im stock motor wise less a slip on. I had a PCV on my old CBR 1000RR and it did wonders. This zx-10 is twitchy... Im probably going to do teh zip tie mod tonight and remove the slack from the cable. Im just looking to make her smooth like all the other sport bikes made -_-

 

Not sure what the zip tie mod is...I have an 08 zx10r and it feels pretty dang smooth the way it is, BUT I have not ridden any other 1000s to compare so I dont really understand what you are talking about. I came from a bunch of 600s and it seems just as smooth as those, but with way more power.

 

I had my G3 reflashed back when Dynotronics was around. Happy with the results. The primary reason I did it was to get rid of the off-throttle fuel cut. I didn't care about any other features really. You can do very similar things with the G3 that you can on the G4, like fuel mapping, ignition timing, speed and rev limit raising and secondary butterfly mapping. The difference is, there's not much performance gain on the G3 like there is on the newer model with these things. I was very happy with the rideability improvements the reflash made. It did make more power with the reflash, but it wasn't the same level as the G4.