I have a 2000 s80 t6 and if i end up rebuilding the transmission since im assuming it will go soon, then id like to stick some horsepower in it too, i wanted to get that chip from eurosporttuner and maybe the exhuast too... But do you guys know if it would be practical to put in a bigger turbo or maybe just a boost controller? how much boost can be pulled from the stock turbos reliably? and is there anything else out there worth looking at for the car? I might stick some suspension mods in too.

Seriously downpipes, catback and an ECU tune will get you good HP and TQ. Do that before you go bigger turbos.