Actually 35R does not require a standalone.
We have gotten 540whp on stock ECU management with upgraded MAF, and I don't see why we can't go further.
If you want just a chip, and you have no way of logging the car, then it is better for you to just get a stage 1 tune.
Your UrS6 is the US version, I guess you never even got any newer code than 551AA.
Here we have 551C and 551E as well.
Anyway, for a stage 1 remap you need to tune fuel, ignition, boost, n75, fuel cut, boost cut.
All in all 6 maps.
Get any chipped file from somewhere and you will find where these things are by comparing them.
I remap these things all the time, my website is here:
http://prj-tuning.com.
I am afraid I will not be of much help yet, but I will probably post all the information eventually, because I am moving on to ME7...
I obviously have my own Stage 1 and Stage1+ software, but I guess offering it for sale would not be in the spirit of this forum.
Good luck.