Price is definitely a factor.. however depends on the size of job as well. When i was in chicago.. i paid $70/hr to www.gocpt.com (Chicago performance) as well as Renn-Art and they are the two best Audi performance shops there. Seems like the prices in this area are quite steep or rather you guys are willing to pay more here.
From what I have seen, more people go to KMD, however, Quattrohaus also is well reccomended and no reason not to consider them. I live in Manhattan (midtown) ... and both are 25-35 minutes away.
Thanks for the feedback so far