Single Turbo 350z Tuning Problems

[cygpro4]

Hi everyone I just installed a powerlab single turbo kit on my 2006 350Z and it is now at the tuner in CT awaiting a tune. We are working on a problem we are having with the fuel delivery. The injectors were just sent out to deatschwerks for flow bench testing because we were not getting consistency from the injectors acrooss all cylinders. my tuner said that when he first started my car after i dropped it off it sounded like it was running bad almost on three cylinders. he came up with the injector inconsistency and recomended i send them out. Deatschwerks responded quickly and said that they tested the injectors and they checked out just fine. They are currently sending the original injectors back to me and now im looking for other causes to this problem. Any Ideas on where to start now that ive cancelled out the injectors??? for those not familiar with the kit as far as fuel upgrades it upgrades the injectors to 600cc and comes with a new walbro 255 lph fuel pump. I chose to stay returnless as this is how the 350z comes stock but i slightly modified the swirl jet and the pressure regulator (both stock) to accomadate for the bigger pump. This was done via detailed instructions on how to accomadate the walbro 255.
Any ideas on where to go next with the diagnosis would really help me and my tuner THANX GUYS Collin

[3point5]

I would look into going 'return' on your fuel system - if nothing more than to be more consistent with heavily-modified z's. I would also look into you ignition setup / coils / plugs.

[cygpro4]

The car ran great before the turbo install. The only thing i changed ignition wise was the plugs and i changed them to ngk one step colder heat range six plugs. I am considering buying a return fuel kit for the adjustability when i build the motor and boost more in the future. However the stock system should be ok for the 6 psi that i will be running on the stock motor I know that other people have kept the stock setup and been ok. I was wondering if maybe i modified the regulator wrong or something but was under the impression that this wouldn't make individual injectors fire more and some less fuel, and i would just be getting low pressure or high pressure across all six evenly. not sure though... was hoping someone who installed this kit or a similar turbo kit had come across a similar issue. I'm using a UTEC from turbo xs and my tuner didn't seem to think this was the problem.