If the curb weight is 3230# and the ITA weight is 2665#, you need to figure out how to get between 850# - 875# out of the car. You've got the obvious 565# difference between curb weight and spec weight, then you have to find ~300# more to take out to offset the cage and the driver. Figure roughly 1.75 lbs/lin. ft. for 1 3/4" x 0.095" DOM mild steel tubing. I seem to recall someone telling me that you need ~60 lin. ft. of tubing to do a typical IT cage.