I assumed you had a built system if planning on running 2 of these monsters. As for the tta, I'm not sure- I'm sure someone with more knowledge will chime in. I was running the 400 with gas and 60 lb injectors (based on advice from a vendor) and my "return line regulator" wouldn't allow the pressure to go below 52psi. I don't know anything about e85, there's only one station I've ever seen it at around me. It may work with e85 and big injectors? Another option is to pulse width modulate the pump but I didn't want to go through the expense and wiring of a pump controller.