I know this has been tossed around several times and I am still unsure of why the timing advance needs to be reversed. After reading the repair manual ignition timing at idle can be 15 plus or minus 5 degrees. When I got the 2 degree advance I was at 15 so now I should be at 17 which is still within factory spec. Even if this adjusts the timing curve 2 degrees across the entire band the original map should be made to cover up to 20 degrees idle timing correct? After reading the manual the 2 degree timing advance seems to only adjust the idle timing hence the reason you feel the truck 'jump' a lil quicker off the line. I'm not sure what the data supports at the rpm range the vkpro is designed for max hp/torque. Hopefully I will have some uprev software here soon so I can play with this a little. I realize the vkpro will somehow affect the stock timing and air/fuel maps but if the stock map is designed on 15 plus or minus 5 degrees I dont see how being within stock setpoints is going to hurt you.