I just put my attitude (145HP) on last weekend, I have been running the HJ since last January 03. I have 315/75 MTR tires and 4:10 gears to compensate for the bigger tires and my speedo is right on. Do I need to put the tire adjustment in the Attitude for the bigger tires to work? The first time I did a 0-60 run it showed 7.8 secinds. I adjusted for the tire size and the next run was 6.0 seconds.