I dont mean to stray off topic, but is it true that the early production model years have different/beefier chain guides? and sometime in 2008 or so they changed them? I dont remember where I got this info from, thought I read it on here once.

You need to research more, the Ecotec engine has used the same guides, no upgrade in 2008

when this happened to me, my chains were stretched. Tech noted that, but re-assembled the chains with new guides and tensioners. 700+ miles later, the chains jumped more than one tooth. Engine went boom. hole in oil pan for counting stars...

REPLACE BOTH CHAINS. I was at 143k miles. And, best of luck. I miss the old gal...

I'm in the middle of this now. Had some "noise" that is resulting in chain/tensioner work. I'll ask about the water pump if the job isn't done yet.

The good news is that my Ally warranty was still valid at 140k. Woo!

Make sure they replace all of the parts not just the chain or chains.
The guides and both tensioners should be changed along with the sprockets

For archive search (and thread hijack)...

Job done. My noise was minor and not easy to hear, nor on every start so I'm glad to have it sorted. I had both actuators replaced, though approval by warranty pending on the second. Other items that may be common and cheap to do while "in there" were added such as:
*INSULATOR. Air Cleaner. Air Cleaner and Silencer. Air Cleaner Intake. Part Number: 12563914
*DUCT. Air Cleaner Intake Part Number: 15865168 ; 15210106