The power plate is just as helpful on a stock engine if not more as the stock plenum has the greatest variance in air flow between cylinders of all the upper plenums. It is one thing that I would advise you to get. I think it will provide the best chance for you to run 17 psi on 93 without any octane boosters or higher octane fuel and you should be able to do that.I am not using a power plate. My car is mostly stock with simple bolt-ons. All I want to do is tune it to it's potential as-is. If you want to know the history on this car, I'm the second owner, PO did more work to the radio than he did on this motor. I got it with the original power master (which failed and now I converted to vacuum), the original turbo (reman) is still in it and has a 3" downpipe, going out to magnaflows, 42lb injectors, applied tech cold air kit, TT chip (v5.6 at 16-18 psi, and 20/18 timing) and a hotwire kit for the pump. Car runs great; but in boost (at about 17psi) it knocks (3 degree rt). What I know now is to decrease boost, increase octane, and check fuel pressure in boost (1:1) at this point. I will do all three and report back. I think I'm just in a tuning scenario and just have to dial her in. Which seems common in these TRs.
Thanks for all the replies and help. Really appreciate it.