It's been a while since the last update. The LS3 is amazing. Lots of power, smooth delivery, and the mileage hasn't been terrible. It's been 15-18 mpg, but I have 35's and 4:10 gears. I'm much happier than I was with the Sprintex. I think the Sprintex would have been a better option if my Rubicon was a manual. The 6L80 trans I've got now is wonderful: smooth and predictable. Here's a couple pics: