Ive had mine done, but found the power is still more top end. I had my 330 done and the curve was much better, but with the Z the power still comes on tap all at 3k pretty much. I had a coil pack down when i first did it, so did not notice it too much, but since being healthy again i would say its worth doing :wink:
I had mine done by CNL remapping, and Colin is renowned for being one of the better mappers, as its not a generic map. If you can get a live map on a rolling road then brilliant, but normally they are 1k plus for a decent one, and only get 25bhp ish, so 15-20 for £300 is very good imo.