Calibration for Gears on Auto

As far as I know, the diablo predator will adjust your speedometer and whatever else you need. That's what I plan on doing when I put my 4.10's in. It's one of the reasons I got a diablo.
 
You can do it with the Dallas SpeedCal for like 80.00. You do not want to do a chip until you finish all your mods.
I suggest that you do the Jmod for your shiftkit. GO to www.tccoa.com. I did the gear change in the tranny to correct my speedo. 96-98 only have to do this. The Speed Cal should take care of yours.