I recall going about 50 on the highway, at 3500rpm! Mine has a 6.5" lift, with 32" Mud Terrains, but I'm going to be swapping to 33" All Terrains! That speed is a little sketchy, but luckily most of my commute I can take secondary roads. Right now, with fuel at the prices it is, I'll just be using my Jeep in the winter, as I use my 1993 Civic for summer. It saves so much fuel, and is just shy of $30 for a full tank that'll last me 2 weeks! My Jeep's average MPG with the lift and tires was around 10-12MPG! No Bueno! I'm definitely thinking about regearing too!