It's surprising how the big motors react to mods just like the little ones. Might just need more capacity for things like water/meth, say 20 or 30 gallons or so.
Main reason I like the Pittsburgh unit is they can program the egt set point to turn it back to stock fuel rate at say 1100 (post turbo) like mine. With water/meth you could keep it under that point and put out some respectible power.
At sea level I've never seen much over 950 egt's post turbo but up high it will hit 1100 pretty quick at the 800 hp setting or about 5 on the Pitts with the 15.8 motor.