port turbo or not???

[turbo buicks]

i just bought a t'netics bb 72 q-trim turbo and the housings are the regular castings. is there any benfit to porting and/or polishing the roughness out of the compressor outlet and/or exhaust inlet? more flow or a waste of time? also it has the 4 bolt on center exhaust housing. whats the differnce b/w this housing and the tangenital housing as far as performance is concerned. i seem to remember someone tellin me the on center is just for cars where tight spaces/fitment is a concern.

thanks