First off, you can't compare a pulley-replacement to a full timinig-belt replacement kit from a reputable vendor. :crazy:
When performing this service on a V6 you should replace both the timing and accessory drive belts, tensioner and idler rollers, the thermostat, and water-pump. Don't forget a full coolant flush! Without the coolant, the dealership normally charges in excess of $390.00 for parts while ECSTuning offers the same kit for less than $260.00 for the same OEM components. This is one service which shouldn't be done half-azzed because we've seen a few members replace just the belts and in time one of the key components fails and causes thousands of dollars in damage.
I went with the dealer stock belt because of the two warranty, as I'm the second owner of the car. It just gave me piece of mind knowing that if something happened to the belt, I can blame it on the dealer for a defective part. Some things are just worth going to the dealer and paying $$$ for.