According to the Saab 9000 Engineering Features book for 1988, they have 160 bhp @ 5500 rpm. That's for us in North America. Looks like UK-spec cars got another 15 hp -- (I think because think they don't have cats??).
No links that I know of, but I've several Saab publications that say 160 hp is all we got. The 1988 Options booklet does say that they sold a Special Tuning Kit that could bump it from 160 to 175 hp. It doesn't give details, but there's lots of info on the web on tweaking the APC to get that.
BTW, in Canada, there was a special model, the 9000 SPG. In 1988, it came with 175 hp, plus other goodies like a body kit, 16" cross spoke wheels, and a lowered suspension.