I have being following this thread from the start, but I haven't commented as I'm not an expert on BMW cars. I'm not in favor on the OP or AA. I guess we'll have to let the facts speak for themselves.
Is there another reason why the OP decided to go public (besides provide his experience with AA)? Does he want partial refund for the engine cost? Is it related with his new business venture? Who fed him information about the two other vehicles that might have AA related issues?
On the other hand, I am not very happy on how AA handled this situation. If OP's former company was a dealer of AA products (
post 1), I'll expect a little more from AA to keep a good business relationship, which both probably benefited of.
Also, OP claims he was a beta tester (
post 587). Doesn’t tester get a free/discounted price on whatever they are testing (depending on what both parties agreed)? OP should be aware of potential problems and AA should be providing better support.
Yes, there might be a legal agreement when the blower was installed, but that doesn't give AA a free pass. In my opinion, if OP drove the vehicle in a way that the car wasn’t tuned for or modified the vehicle after AA installation, then it should be OP's fault. However, if AA didn't install or tune the car properly, then it should be AA fault. It also could have being OP car had a weak engine from the start.
I guess the bottom line is to ask your SC kit provider on what is covered under warranty before making a purchase.