the turbo+ is kind of like a saab apc without the knock boost adjust (afaik); it bleeds about 20hp worth of boost dump off the wastegate (i.e., you get 20 more horsepower because the wastegate thinks you're not boosting enough to open) at full throttle and above 4000 rpm.

If you remove the turbo+, you need to remove the turbo+ brain, the solenoid, and reconnect the tubes. Then install the saab apc per the volvo performance site instructions. Main thing about the saab apc is ability to run increased boost depending on engine knock performance. The original saab apc was designed to enable the engine to run on regular at reduced performance (I did it once on my 84 900T and it was REALLY reduced...slug).

But I'd still just run super premium and a dawes device with a rising rate fuel pressure regulator. Lots cheaper, less aggravation. Wouldn't hurt to get Dawes' LED 02 sensor indicator...tells you when you lean out at wot...not good thing to do. And if you're too rich, just wastes gas and in fact robs you of horsepower.

I presume you have seen the volvo APC site.

Have a look through the archives at www.saabnet.com, esp the 900 classic messageboard.

There is an APC site (can't remember the url) that explains modifications to them (higher boost / remove boost taper etc), and yes you can trick it up to be changed from within the cabin - but do you really want to?

Note that there are several contradictory explainations as to how to adjust boost. The volvo site and some saab sites appear to be misleading in this regard - given what is being dicussed at saabnet.

Save yourself a ton of money and add a wastegate control valve. See http://pages.cthome.net/gus for complete info. Also Dawes Devices sells the compete valve for about $25. This little valve delays the wastegate fron bypassing the turbo until a preset pressure is achived. Lots of power and alot of satisfaction.