you need injectors and afm, nistune are great (we are one of their biggest customers) but not on r33, go powerfc. We pull 2 or 3 nistunes out of r33 a month that have been tuned elsewhere that just dont perform right. The dont work properley as you have to retro fit another ecu from R32 or Z32 into the r33, there are certain background trims that can play havoc that are not adjustable.