Remember when you're measuring a change in your mileage to compensate for the larger diameter of the tires.
When I went to 33s, with a 4.10 axle and 4.0, I lost maybe 1 mpg after compensating for the change in gears. My new truck with 31s gets about the same mileage as my old truck, so there's a negligible difference in mpg.
And with 32s, you ought to be alright with a 4.0 and 3.73s. I say go for it. TSLs are badass. Just don't cry about the terrible treadlife on pavement.