Fuel surge tank with stock pump and FPCM ?

[AZ03Cobra]

While I was changing my pump last week, I realized how far forward it is in the 31 gallon tank in my 09 Escalade ESV, so the thought of twin in tank pumps without a factory bowl scares me, and would probably mean I couldn't run the tank under 1/2 and still get on it. With my Whipple/cam/6.2 setup, I want to switch it over to E85 and the only "safe" method I can think of involves putting a surge tank with twin pumps in the secondary battery location under the hood. I have been reading of a couple instances on other GMs where they installed a fuel pressure regulator on the stock feed and set it to 58 PSI, then had the return to the surge tank, then the surge tank pumps to the fuel rails, then the surge tank return back to the tank. This seems overly complicated, but I guess the idea was to allow the factory fuel pressure and FPCM to see pressure, where as directly feeding the surge tank, it wouldn't.

My question to those who may know, do I have to put a regulator on the stock fuel pump line so it sees a restriction, or if it is allowed to just open feed the surge tank, will it throw codes and/or cut off fuel flow? I have never done a fuel system involving a FPCM, and didnt know what parameters id have to change, if any, to make this work with the stock pump as a feed pump to the surge tank. I just dont see any other ways of making the stock pump location work for an aftermarket setup outside of doing in tank pumps AND a surge tank, then hoping it all works without starving the tank if I do run it below 1/2 tank, or burning up the pumps.

[smokeshow]

I've done it without a restriction on the feed line. Just circulated from the fuel tank into the surge tank and then back to the fuel tank. Didn't give me any issues.