I believe your best bet is using ECU Editor. Clean install and not a bunch of extra cables and connectors. You will spend more money on all of the Powercommander extras to run 50hp+ of nitrous.
I have all of Greg/Petrik stuff to make the nitrous experience simple and fun. I ran a 50hp shot, no timing retard(on pump you may try -2 which can be done with through the ECU), map switch when nitrous is activated at pre-determined 6-10k window for nitrous flow, 1st gear lockout to prevent nitrous flow in 1st gear.