Replace timing chain or just timing chain tensioner? on 1998 BMW M3

My M3 is making a rattling noise that is getting louder over time only when the car is in gear. The noise seems to be coming from the front of the engine where the timing chain is located. A technician told me that the tensioner was getting worn. Should I replace the timing chain or just the tensioner?

Asked by for the 1998 BMW M3
If your going to all the trouble to take apart the front of the engine, replace the timing chain, gears and the tensioner. You don't want to have to perform this job twice.