ERZ to motordyne ART pipes

triadz

Ok dyno has been completed final numbers with the stillen intake and motordyne test pipes 297whp 253 tq, the guy tuning my car said he tried and tried but couldn't squeeze anything else out of that set up, he told me that he thought the y pipe could be causing to much back pressure or something along those lines, and at an h or x pipe would be a more ideal setup for my car...any thoughts. O the 297 was also the last pull of the day so the car was very hot

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H and R springs, top speed cat back, motordyne art pipes, stillen gen 3.