And as for the little mishap, i think you should scare them, go in there and DEMAND to get there full legal name of the business (the name they used to register there business)
say your going to say "worst shop ever" on the BBB and if that doesnt work, let them know that you are going to take them to the small claims court and that you have a certified bmw tech that checked your vehicle and that there is no problems with ur suspension, and honestly the 500 bucks isnt worth going to the claims department for, but atleast they might refund your money or give you free tires
..... and btw i did this and it worked for me with a different company, so lets hope it works for you, and i actually took the time (to send my brother
) tot he court house and get a small claims application form, and i took it to the shop with me, while i was on my rant!!