On an 8V 2.0 engine.....getting huge engine and gearbox rocking car shaking surge low down the rev limit even on part throttle - its a T34 0.48 derivative with a 3" inlet on the compressor side running about 18/19psi

How do I help stop this - anything I can do whilst the head is off???

Obviously if I turn the pressure down it helps but then the car doesnt feel as fast.....

Any ideas???