That sounds like a fun setup. We just bumped my waste gate duty up some to allow my psi up a little more. Stock my car was 11psi. With a ready made "Off the Shelf Tune"(one size fits all) from the largest company selling reflash tools i was running about 14psi. I'm still in the process of fine tuning the ECU with a custom made tune from a turbo shop we were running 16psi and today just bumped it up to 17.5psi. Also just pulled back the timing on the high rev area. Haven't tested it yet but it should yield a bit more umph. This turbo would never get close to 20 something though(nor would I want it to). I really would like to swap turbos for a mitsubishi style (well I would really love a garret ball bearing but aint got money for that) TD05 18g or 20g to give some more volume at higher RPM cause this stock turbo falls flat on it's face past 3800 rpm and my torque suffers pretty bad because of it.