this is a pretty late reply, but this indy place has a bunch of very favorable reviews -
http://sanantonio.citysearch.com/pro...to_repair.html. i've been meaning to check it out should i ever have any issues that the san anton bmw folks are either unable to diagnose or too lazy to do a proper job.
alternatively, look for the owner, karen mgerian, at 'mgm auto' -
http://sanantonio.citysearch.com/pro...to_repair.html. my friend bought a '00 540i from him some months back and he specializes in bmw and mercedes. very shady looking place, but his mechanical knowledge is pretty sound. plus, he can provide contacts at bmw of san antonio where he says a few of his close friends work at.