A very good engine. Similar bottom end top the old POS M40 but a much nicer head with roller rockers and indeed a chain for the cam. The only problems these have are the head gasket (well known for it now they're getting old) but they're a piece of piss to change. the M43 is a nice engine to work on and the head comes off in an hour. Some suffer from excessive crank end float. These are the badly maintained shitters thrashed to death on old oil where the thrust washers weld to the crank and then eat into the block. I've seen a few where the block is badly corroded and they suffer from not having proper anti freeze.
Throttle discs also stick in the throttle body but it's 30 minutes to remove the TB, polish the ridge out with 400 grit and reassemble.
Got hold of a one owner from new, from Cambridge BMW, FSH loads of stamps first few BMW, then a specialist who I know, 106k. Really tidy. Nice daily driver, if a little lethargic!