timing

Is there something in particular I should be looking for in a timing chain kit for a 3.5? My main concern is the quality of the guides - don't want to be back in the P0017 club for a while.

I was replacing a bad cylinder head on my '05 3.5 I5 Colorado. While reattaching the the timing chain, I cracked the camshaft tensioner guide rail on the intake side. The rubber part seems to be holding it together but its snapped right in the middle. If I don't replace it now will I regret...