If your engine is relatively stock, I would stick with a stock type replacement with the steel cam gear. I replaced mine at 60,000 and found 3 cracks on the cam gear.
Dynagear or a Cloyes replacement is available at your local auto parts store. the set of gears, chain and a new tensioner was about 20~25 bucks. Also pick up a roller cam button at your local GM dealer. And while you've got it down that far, it's a good idea to go ahead and drop the oil pan @ clean the oil screen and replace your leaking rear main seal.