This is what I used on my 1988 930.
https://a.co/d/hys2S1d
https://a.co/d/bmZRWL1
https://a.co/d/5xqtX6B
Not sure of any power increase, but you can't mistake the sound of that turbo winding up and dumping now...
And its just so much cleaner under the lid. Very happy with the finished product for under $100.
