I'm no expert on 900 trannys; los of people say they're made of glass. Depending on mileage and driving style, you should be okay. Rolling on the power and not hammering it through the gears probably has a lot to do with life expectancy.
I would recommend upgrading to a 9000 clutch kit to hold that extra power. If I recall correctly, a SACHS 9000 clutch safely holds 270hp. Only the 1990-1993 9000 turbo clutch will fit.
1995 9000 Aero - Jordan Pagano tuned 390hp
2002 9-3 Viggen vert - Jordan Pagano tuned 300hp
2004 9-5 Aero Wagon