you can get the 472 to spool up pretty fast if you take some time and get the tune dialed in.
I would imagine you wont be too impressed with the 68, go with the 72. it will move more air, keep egts down, and make more power.
i have used about the twice reccomended concerntration of "diesel kleen" in a couple tanks of fuel and that cleared mine up, this was about 2 years ago and not a problem since.
if that doesnt work you can get a new regulator for pretty reasonable.
if its the water pump you should be able to barely hear it at idle and clearly at about 1100rpm.
I doubt that atf in the powersteering would cause problems, i know of quite a few people that have run it in a pinch.