Definitely do your homework, as every chip is different and the prices range. I'm not sure on the S40, but on the 850 changing the ECU is MUCH easier than say a Golf Mk IV. I've done both conversions.
I've never owned an Upsolute chip, but I haven't heard anything bad about them. The only experience I have with them is in a friend's GTI 1.8T. That particular version of their software had less torque than the equivalent version by APR at the time, but stuff like that changes all the time with updates etc and APR doesn't make Volvo products anyway. So it reall doesn't apply.
I know IPD offers their satisfaction guarantee. I don't think anyone offers dash adjustability.
There are other companies out there. IPD/TME (already mentioned), GIAC, MVP/Steffansson, Heico Sportiv, Superchips, etc.
I have a chip from upsolute on my T4 year 2002. The feeling of driving the car is total different. It is more direct and you can feel the gain on power (hp and Nm). I have send them my ECU and they have remove the original chip and then insert a socket. Copy the original and chip them. Now I have back the ECU with modified chip and the original for exchange when needed. Now I use a octane booster and the car drives smother.