I recently purchases an exceptionally clean '91 300CE coupe (M104 engine) for my wife with 148K on it. I was hoping to hear from anyone who has the same engine as to the life of the chain and at what point one should consider replacing the guides, tensioner or chain itself. At this point the car is running fine and there is no chain rattle or noise of any kind...can someone offer me some history and advise on this.

thanks, Antonino