Looking for some advice....

Local dealer (not a bmw dealer) has an '11 model X5 35i with only 37K miles. Really nice looking car and I've negotiated it down to a fair price - not cheap by any means, but fair.

The thing that gives me pause is that looking at the carfax, the engine was replaced a couple thousand miles ago by the BMW dealer. It's out of warranty since the 4 years have expired, and its not CPO either. So I'd be buying an '11 model with low miles and almost no miles on the engine.

I'm not sure if that's a good thing...or perhaps a warning sign of a problem plagued vehicle! Never heard of an engine needing replacement at such a low mileage.

Any advice on what y'all would do? Would you be more likely to purchase a low mile X5 with a new engine from the bmw dealer....or less likely?