The kit ECU for the '08 Zx10 is cheaper than a PC, and offers a lot more adjustment(fuel/ign mapping, TC adjustments, seconday tb adjustments, launch control, injector trim, pit lane speed etc..). Your stock ECU is non-adjustable.
We've always used kit ECU's on all of our racebikes, and have never used the TRE on 'em. Stock, the ZX-10 is a handful to launch, and is more than capable of accelerating quicker than most people can handle. The stock ign timing adjusts in the lower gears to help save your transmission. As I wrote earlier, the kit ECU allows for you to adjust ign timing everywhere if you want to.