Originally Posted by Skyline

I'd be willing to bet money on that one.

I've owned BMWs for 43 years, and I've never, ever, heard of a BMW dealer installing a used motor. Or ANY used part for that matter. I doubt any other marques dealer would do so either, the liability is too much, and I'd bet their franchise rules prohibit this. I've seen BMW dealers install short blocks to MANY V8's, (an absolutely massive job), and do other engine rebuilds on site. When it comes to an engine replacement, they work at the pleasure of BMW NA. There can be "goodwill" repairs, but those don't happen for customers who bring in a problem used vehicle bought elsewhere.