I always recommend taking my vehicles to a dealer. When I bought my 2000 tundra 4.7l used, it had an after-market water pump due to the fact that the guy who had the truck before me didn't take it to the dealer to get the timing belt replaced. Well after about 20k miles on the timing belt replacement, the water pump started leaking antifreeze on the timing belt causing it to stretch over time, and then break. Due to the fact that we have noninterference engines, this could be fatal and cost a good 4k to fix. Thank god my engine was still good and the compression in all eight cylinders was good.
If you do take it to a shop other than the dealer, MAKE SURE THEY USE ONLY OEM PARTS!
After market parts usually have design flaws like the water pump that was on my truck. In fact, every part on my truck has given me no trouble except for my aftermarket alarm system, and my Roll-N-Lock
tonneau cover which are the only two after market parts now.