N20 328i timing chains

[JuanCarlosFandango]

I have a 2012 328i currently on 76,000 miles. I've looked all over the Internet and found loads of conflicting information on timing chains, so thought I'd come here for even more!

I understand there were some issues with the pulleys which can lead to engine destruction, but can't seem to get any answer on whether this is just a few cars with defective tensioners or likely on all of them?

Have I got a good one and needn't worry? Or should I get it changed before it goes wrong?

Secondly, estimates of getting it changed seem to range from £600 - pretty much infinity. Interested to hear what others have spent?

[I-am-the-reverend]

They do have trouble and from what I've heard, mainly the plastic guides breaking - early ones have problems with the oil pump chain.

It's about a grand to get it all done.