Yeah the GM Map is a 3bar I think, you need to actually have a calibration for it or a S60 ecu. Gary at Relentless Performance should have a 3bar cal. You could use that with larger injectors and run the boost up without the need for rising rate regulators, extra injectors, diodes and the likes. IMHO a 3bar cal is really the way to go, less hassle, more reliable, and less tuning variables.

89's are roller cam right? If so then the older slider cams would probably not be a good idea with it because the head won't have the extra oil squirters machined in.