I did the same as you peachy. To be honest, it is a good and fairly cheap upgrade to do, but i think your better off going straight to hybrid and making it one step instead of 2, if thats the road you want to go down?
As for how it feels, you can definatly feel the difference in power, ok its not MASSIVE but noticable. When i first got mine fitted and mapped, it makes a much nicer spool up sound, can really hear it whistle. It spools up just as fast as the ko3 and will hold the power until about 5.5k then you still do feel it tail off, but ive already changed gears by that point. It will still lose power like the ko3 does, so dont expect it to pull all the way to the redline