The most accurate will be pre turbo where the turbo mounts, as far as safe egt's 1200 is a good nuber to stay around higher numbers are ok in short burst, i tow at 1250most of the time with now issues, but just set you defeuling to 1300 or 1350 so it will start to defuel around 1200 - 1250 but some trucks are different, just play with it a little and watch the back down gauge on the monitor to get it where you want it. As far as the boost fooler, i not sure about 3rd gens, just run it and see if any codes come up or see how much boost you get, but i wouldn't think you would since its -6 is electronically controlled. DD