So far, as per my humble knowledge and from mechanics which I like to TCSS with them, usually MT performance cars will have the tendency to replace timing chain due to the nature of the habitual driving. For normal AT and CVT, it really need a high mileage to wear a timing chain since it come with a chain tensioner as built in for most cars nowadays.
What the mechanic said is true if timing chain is worn and stretched as it will vibrate thus that where the sound should be.
So have you solve your pinging noise yet ?