Ok, I have called the following shops about my timing chain which probably has 180k on it and is not making any noise. This is what they said:

JP Motors: New Haven, change chain at 100k for $650

MB dealer North Haven: change chain at 100k for $575

Eurpoea Motors, New Haven: change chanin at 100k for $700

North Haven For. Auto and Glastonbury For. Auto: do not change change until it starts to make noise.

It sure seems odd that the low bid was at the dealer. No one seems at all interested in measuring the chain stretch.