Timing Belt or Chain...when to replace

[SunLitSandMax00SE]

I am taking my M to get its' 90k service in and wanted to know a little about the timing belt or chain and when it should be changed and also what I should be looking at for how much to spend on getting it replaced.

[M45Runner]

The engine in the M uses timing chain, which do not need to be replaced on a scheduled basis - only when it start to rattle or fail. Most timing chain last well over 200K miles - that is one of the reasons I bought the M - One less major item to worry about.

Let us know how much they charge you for the 90K service at the dealer (I would assume).