The MKIII has more power than the Racing of 2007/2008, so next time tell your friend to tune the MKIII the right way! And that means not too much downhaul, quite a lot of belly.
It took me some time too to tune the MKIII ok, but after you' ve found how to do it the MKIII burns on the water.
Of course the NP Racing isn't bad at all, it's a great stable and powerful sail too but quite a bit heavier and the light feeling of the MKIII makes it controllable and fast. You should try the MKIII 7.0 (tuned ok) with the isonic 101 - fantastic!