another cheap way to lower a truck effectively would be to take the shocks apart, and put more limiters in the shocks, when i ran carpet i put a good 1/4" of fuel tubing inside the shocks all the way around, dropped the truck right now
even with full size tires, trued tires you could drop it all the way down to the 5mm tcs run
i used to run RR-Red Spring 40wt, RF - Green Spring 40wt, LR-Red Spring 30wt, LF- Blue Spring 30wt, all with the 1/4" of limiters. (in the pictures it was blue front, red rear when i didn't have the foamies trued short lol)
***this was an OVAL setup***
for road course i would think something along the lines of Red or Gold Rears, with Blue or Gold Fronts. higher wt fluid - 40+ other then that shorter turnbuckles, taller angle shocks.