Just wanted to point a few things related to this survey. The fact that people are having premature wear of pump chain/balance shaft drive does not show up in the results. After reviewing the posts several times, this is what I see:
briguy66 --------- 2005, 151K, had to replace chain
OH3Hoser -------- 2005, 95K, had to replace chain
Whitehouseauto -- 200?, 95K, loose chain - I assume replaced
JCaimhigher ------ 2005, 65K, complete failure
Bookworm -------- 2005, ?K , replaced chain and hex drive
If Whitehouseauto is a 2005, that is a problem with 5 out of 32 for the 2005's, none for the 2004's. Thats would be 15.6% of 2005's, ranging from 65K to 151K.