Torque converter locks up will be messed up yes, I just lived with it, did it to a VS V6 auto and a VX V6 auto, 3.23 on the VS & 3.46 (V8 manual diff) on the VX, to be honest the box's took a few days to learn to change at red line but soon adapted, from memory the PPM change can be done on VS, definatley VX, to make speedo run true, BUT, I am getting older and memory a little fuzzy lol, pretty sure it worked but.