[casper gt]

im relatively sure L/T's will throw a CEL so if you dont mind the light being on i would get those 1st. I think a pair of MIL eliminators will take care of the light. a tuner can do the same, just turn off the O2 sensors with if (if you have the right tuner that is)

with L/T if you get a light (not all do, but most will) it's the front O2's causing it & you can't use MIL eliminators on the front O2's, so you'll need the tuner any way. as to the gears, you'll need the tuner to recalibrate the speedometer anyway so, I vote tuner 1st.