the cool fuel should be on the return side before going back to the pump. Send me your email and I'll dig up some pics of my setup to give you a clear picture. Works perfectly. And, without the boost-ref regulator. You should really think about getting that out of there. The motor will run so much better without it. You will have to find someone to tune it if you're not willing to try it yourself but it will make a huge difference in the long run.
How much boost are you running? Still using the stock injectors?

Griswald, will PM you my email for pics. Are you supplying both ends of the rail then?

Its a stock engine with 5lb boost, stock injectors, 1 bar MAP sensor. What would you recommend for self tuning something like this? I assume I would also need a 2 bar MAP sensor and larger injectors?

I ran stock injectors at 50lbs pressure, mefi4 ecm with 2bar map and tuned myself with MefiBurn/Scanner Pro. M1 Procharger @ 6lbs. I'll share my experience via email and/or a phone call or two. Send me your # as well.

X 1000. The ATI 'fuel system' sucks major Donkey Dick. Excuse the french.

I'd take Griswald up with his offer.

Yes i look forward to talking with griswald, but it does seem like I have a weird issue here. I cant even set a constant 50lbs of fuel pressure with only the aeromotive regulator- while the boost referenced regulator is bypassed completely.

because you have no regulation coming from the pump to that end port...

The onlu fuel pressure anyone wants to see or care about is the pressure the fuel injectors see. Otherwise known as 'the rail pressure.Therefore, it must be before any regulator on an EFI system that has a return line.

Oh, just as a heads up. If you have a permanently mounted liquid filled guage near a heat source, it will read higher and higher as it gets hotter and hotter...lying to you....making you think your fuel psi keeps changing on it's own...even if the fuel psi isn't actually changing.

Just a suggestion, come out of the tank to a 100 micron or less filter, go to the pump, out of the pump to a 10 micron or less filter, go to the fuel rail, come out of the fuel rail to the regulator, return back to the tank. Read your pressure at the regulator. Keep the boost referenced regulator so the fuel pressure increases as you build boost pressure in the intake manifold, Weldon makes a good regulator. Skip the cool fuel, sending it back to the tank will work just fine.

If you haven't already done it I would suggest you check the size of the pick up in the tank. Prochargers like a LOT of top end fuel.