You can crank the line pressures so high that you can crack the tranny casing..only if you wanna... You can tune in two sets of line pressures with the Tow/Haul button. I'd do a 65 regular; 85 when the Tow/Haul button is pushed... If I wasn't going to have a complete tranny build done, I would for sure do a Superior shift kit (or Trans-go HD2), 2nd and 4th billet servos, 1-2 accumulator piston, forward clutch accumulator piston, separator plate, and the high rev spring kit. I haven't heard of may people drilling out the 1-2 feedhole any bigger, but do go ahead and drill out the 2-3 feedhole .110 bigger and the 3-4 feedhole .125 bigger...