I have the Terra flex ST 3.5. With falcon 3.3 adjustable shocks Yes I did regear to 4.88 I was going to regear with the 37 so I decided go 38!!! It runs great now more peppy then stock very smooth quite even at 80-85 only con is MPG avg is 16.2 but no big deal because it looks cool !!!!what lift do you have with the 38s? did you have to regear and do anything else to run those tires?