I've read TONS of info on power steering stuff, both here and on Pirate, and in many conversations. There is no real consensus on the subject. People have had good and bad experiences with every possible product and setup. A couple of things seem to be consistant. You need a cooler, which can be a small size trans cooler, it's very simple to install one in the low pressure return line. If you are having problems with parts going out (this one is a tough one), like replace a pump and then it goes out again, the actual problem can be contamination in the system, metal flakes from the failed part in the fluid that eventually take out the new part. You're not there yet, but many of us did not fix ongoing power steering system problems until we replaced every part in the system. Beyond that, everyone's experience and success is extremely varied. One thing, a TC pump that has the pressure bumped up too much can have a short life, especially if it's a used pump.
Relating to your specific question, while some have had problems with both an AGR or PSC pump, most people have had good experience running the modified pumps. I have an AGR pump on the XJ that has run trouble free for at least 8 years, both with and without ram assist. I ran a PSC pump on the buggy, but had issues with other parts in the system and replaced everything, and now run a Tommy Lee (Lee Mfg) modified TC pump. I will say that folks that make the jump to the P pump seem to be very happy with it, and it is a good pump for running assist or anything else that you might do with the steering down the road.
