I think you are SOL with Suntrup. Why would they deal with you when the chances of you doing any future business with them is non-existent? You should probably plead your case with your home BMW shop's service manager to see if he/she will cut you a break on their hourly shop rate in return for all your future service business. If they give you a break on price call up the GM at Suntrup and see if he/she will split it with you to make you go away and stop putting up bad press on the internet.
This is a much smaller case but when I bought my 335 I didn't notice a bubble in the sidewall until I got home with it. The dealer tried to accuse me of hitting a curb in the 5 mile journey from the lot to my garage but in the end he ended up splitting the $375 with me to fix the tire. However, he has some chance of doing business with me in the future where Suntrup doesn't with you. I really don't think you have a chance in court unless you can prove they knew about the wire condition prior to your purchase. Without a service record stating such you are pretty much screwed there. This is just bad luck, unfortunately, and you are going to have to rely on mercy from the selling dealer or your repairing dealer. Sorry to hear it but just get it fixed and forget about it. Hopefully it isn't a bigger issue.
2007 Titanium Silver 335i Sedan w/Sport, Premium, Comfort Access, Steptronic...