Ok I have a Gsr turbo'd with CP 9:1 comp pistons, Eagle H beam rods, Walbro 255, 3 Bar map, RC 550's, SC61 turbo, Neukin ramhorn manifold and 3" downpipe, Tial 38mm wastegate, AEM EMS. Now my question is I had my car tuned with a inline pro cast manifold and 2.5 inch exhaust..I upgraded to the neukin manifold and 3" exhaust and had it retuned..When I had the cast manifold my car ran great Now after the retune with the neukin manifold I have a problem that my tuner nor anyone can figure out So I hope someone here can..When I push 100% on the throttle it feels strong but like something is holding it back then at 5500rpms something opens or turns loose and it really picks up..When in lower rpms you can hear the turbo spooling but it just dont move like it should..What could be doing this?I really need help If anyone knows Please help