My car was on the dyno on friday, after getting a few things done to the motor (rb30det). The tuner says its getting heaps of compressor surge. Its a small turbo for the size of the motor; a T3/T4 .63exhaust (thats all i know at this stage

Its got a genuine blitz sequential job on it at the moment. My tuner reckoned to run a standard type bov aswell as the one thats on there. Does anyone else do this. Would this just be because the standard ones have a lighter spring in them or something? How would a standard one be more efficient? And can i use any type of standard turbo vehicles bov?
Also having troubles with the internal wastegate not holding boost, i think the spring in it is just not quality enough. Currently 160kw at 3800rpm, then boost starts getting out of control there.
Car is still on dyno, will be on it all tomorrow.