Here are a couple points to consider.
1) If a Regulated return is used, be aware that it takes a lot more heat to achieve safe operating temps. Even if it is a closed loop, a large FPHE will be required to get the oil hot enough. ALL heat must be in the oil before it goes ito the heads because the fuel goes thru the heads so fast that it does not have time to heat up.
2) A regulated return is not really necessary with stock injectors.
3) Remember a return valve will be required, howver, it makes for super fast purge times with a regulated return.
4) If a RR is used, I highly recomend the closed loop system with return fuel directed pre-pump, and then thru the system. Plumbed in this fashion, shorter filter life will be experienced because ALL fuel must go thru the filter, most likely numerous times.
5) A RR makes for a very quiet injection with large single shots, I like it for that.......
I run a regulated return on D2 and VO. I'm gathering parts for the GF's Ex while the tank is being fabbed. I will not be running a RR on that truck until stage 2's go in, if I every do it