Looking to put this system on my off road car, going from an MEFI-4B

I have a 2005 Chevy 5.3L L33 with a Lingenfelter GT 2-3 Cam, I have an Ls6 Manifold and 42LB Bosch EV-1 Injectors, and I don't run an O2 Sensor, or a MAF.

Am I going to have problems?

Does the Rail have a regulator built in - I watched the 57 chevy video and it looked like they just hooked up the return to the tank?

If no problems, which model would I buy?