Maximum power depends alot of the chip you have. With that intercooler, you can run MUCH more ignition advance on high boost, than with a std. IC. If you're not taking advantage of that, then you will lose substantial power. In anycase, the fun begins at 1bar boost, but beware, the standard turbo will be glowing red in no time if you're doing longer sprints, such as trackdays. 200bhp should be acchieved, but not much more with the small turbo. Try a T3 from a turbo Volvo 240 or 740. I think the downpipe and the wastegate assembly form the RST will fit straigth on. That will give you a larger compressor TRIM and a .48 exhaust hausing.