Wait you have a 550xi? That may very well be part of your problem. Not sure what BMW's AWD system involves mechanically but you probably may NOT be able to break all 4 tires free in a massive cloud of tire smoke you seek as BMW's electronics may just prevent such antics. I've broken free my rears a few times but I have a RWD 550i not the AWD version. I've driven a C4S AWD on the track and even getting it to break free all 4 wheels as you suggest is difficult unless I am using launch control. Just a nature of the system design where the electronic nannies intervene way to early. Its not an AMG car with 600hp and 800 torque mind you where the electronic nannies are constantly fighting to put you in ditch in normal driving! LOL
Also the fact that you have an F10 550i vs an F10 M5 may be an issue. Do you have the Sport AT or the normal AT with your car or 6spd? The F10 M5 has the DCT if you recall which has launch control and is known for such antics also. I have the Sport AT and with Stage 3 I have noticed a significant amount of hp and yes torque with the car. It is blindingly quick and definately you feel the difference between my pre-Dinan vehicle and now.
Sorry you're disappointed...not sure what you were hoping for in the car but seeing that you came from an e92 M3 the F10 550i is NOT that car nor is it supposed to be. The M3 is a hooligan and high reving v8 which you can do all that with...the 550 is a different animal altogether! Just as quick and probably quicker but if you want that m3 type of glory you may need to step up to an M5 if that's what you seek. I don't agree in that I think properly tuned the F10 is about 85-90% of the M5 on a public road. But hey to each his own...liking car wise.
Good luck with your refund. Not sure you'll get far and even if you take it up with Dinan the regional rep will probably get involved and it may take a min or two to get a favorable resolution and even then...I've never heard of anyone getting a software re-program and refund...and that's after having 3 different M cars and Dinan on 4 of them I've just not seen it happen yet. Good luck tho and keep us informed.