I was using the same jabsco pump you guys are talking about and havent had a problem with it in the 3yrs i have been running it. I was using a jegs 3gal fuel cell in the trunk and a large b&m trans cooler for the heat exchanger front mounted. I was running the pwr barrel large 4in unit for an i/c, i think i was running 3/4 in lines, my total system coolant/water vol was around 5 gallons.
I recently sold all my water to air stuff to a friend of mine so i will be using an air to air unit now
, the reason i went to the air to air is i got into an accident with my nx, and went with a new front bumper that has a very large opening and in my opinion would look stupid not to have a front mount behind it.
There is also an ebay company if you search under water to air intercooler that makes a nice alum. heat exchanger that would work very good, and its cheap.