I am thinking about getting a programmer for my 98 3.9 to give me some more power and adjust the speedometer for larger tires. What is the best programmer to get and is the gain in power enough to justify the cost?

 

Not many give the option for tire size. The tuner, by itself, may add a bit more power/torque, but, it works best with supporting mods. (anything to help the engine breathe better.)

 

I have an intake, a 2.5" exhaust with no cat and high flow muffler.

 

So for tire size do I have to change the speedometer gear in the transfer case like on the Jeep and Ram trucks of the same era?

 

I think the 98 uses the rear wheel speed sensor on the rear diff for vehicle speed......

 

Ideal method is to use SCT for the tuning, and find somebody with a Snap-On Modus or a Chrysler DRB3 to change the speedometer. The speedometer is controlled by the ABS system, and requires a tool that can access the ABS system (not many of which exist)