Timing belt/chain preventative replacement?

[weingarm]

My father owns a 2003 Z4 2.5i roadster with about 61,000 miles. Original owner, only adds about 2000 miles/year now. Runs great.

Keeps all the maintenance up-to-date.

Wants to know if or when he should be replacing the timing belt/chain and/or guides. I’m aware that other BMW engines have had issues with timing chains - is the 2.5i engine one to worry about?

Is there any other preventative maintenance he should be doing besides regular oil changes, brakes, etc? He’s already replaced the hydraulic pump for the power top which now works perfectly.