Awesome info about the fans, it's one of those things that trial and error in my case, so this gives me a great head-start. I may try one just to start with to handle idling situations, they get expensive.
It's a cool engine to work with - you are putting it in a truck 20years newer than the motor, and I am putting it in one 20years older. If you want to look at p-pump stuff "the pulloff" website has a great classifieds/parts section with some good deals on pumps.
That being said, if you feel you are making almost 350hp, how much farther do you want to go anyway I suppose? If you have the rack travel maxed out, you are going to be in the 180cc range I have heard, which could get you to that HP (I have heard almost 2hp/cc is attainable) especially with that bigger turbo and intercooler.
The MW pump is not a bad pump, just runs out of room for increases. From a longevity perspective, I bet a p-pump is no better/worse. Maybe neverenufhp can comment.