Justin,
Saab wouldn't match the 225bhp Aero engine with the auto box, it only got the normal FPT 200bhp, but the auto box was standard with the 210bhp V6...??!!?!?
With the auto trans expertise in the US being more so than here in the UK/Europe, (manual boxes being the prefered performance option) I would think it's more likely that you'll find somewhere your side of the pond to upgrade, if possible, the Saab 4 speed auto box.
If not you'll have to be prepared to change transmissions on a regular basis, if wanting to put that many horses through the standard auto box. Although, I suspect it's the significant torque increase at lower revs that will do the damage, rather than higher bhp, depending on your daily driving style. Stop light to stop light drag racing would kill the box very quickly I would guess...