I just had a mopar performance computer installed in my truck and all I have to say is it made a big difference. My truck has the factory 3.55 gears with 36" swmapers so the throttle response was very sluggish. Even with the crappy gears the performance computer really helped my acceleration. I can now easily pass cars on the highway and can squeal the swampers on take off. The only downside is the computer only works with premium gas. However the computer does have better fuel efficiency than the factory unit. It cost me $350 but it was well worth it, supposedly 30-40 extra hp.