My old 2008 3.8 has been a sweet engine. Sure, it's no powerhouse, but it has been adequate. I've got a 6 speed with 4.10 gears (Rubicon) and I run 33" pizza cutter KM2's. It does fine on the highway and off-road. Funny thing about that 3.8. It started using oil at about 40k, drinking up to 1 quart per 1,000 miles. It now has 120k miles and has decided to stop using oil. I noticed reduced consumption around 116,000 miles, going to 1/4 quart, then maybe 1/8. Yesterday, I checked it after another 1,000 miles and it had used zero oil! I don't get it, but this might be the first self-healing engine I've ever owned! Anyway, I drove a 2017 JK for a week that had 35's and a 4" lift with 3.73 gears and an auto. The 3.6 most certainly makes more power. I'm sure with a similar set up to my old JK, the difference would be night and day. I still love my old 3.8, though. I have a new JL Rubicon coming in January (hopefully), but I'm keeping the old JK. It is just too good to let go and I have the lifetime powertrain warranty. The Jeep runs and looks like new.