I bought a 2009 335i from Luxury three weeks ago. I was leery and very cautious after reading all that was written in this post. All the cars I considered had Carfax available for download and yes some of them were lemons (dealer buy backs). No way I would buy dealer buyback but Luxury did not try to hide that they sell them.
I was EXTREMELY happy with how the sale was handled. I did my homework before going to Chicago to ensure that the car was as described. I did pay to have Orland Park do a pre-purchase inspection (Luxury dropped off and picked up the car from Orland) which confirmed the car was as described by Luxury.
Reading these posts I find the people complaining generally:
1. Did not research on the car prior to showing up at Luxury (whose fault is that?) or
2. Tried to negotiate the price (not going to happen)
Do your homework and you won't have any problems with Luxury...