[BBC71Nova]

I recently went from a '00 5.3 ext cab to a '10 Sierra crew cab w/6.2L. The new truck is noticeably heavier but the 6.2L is a beast. Especially coupled to the 6l80 with the ultra low first gear they have. I haven't towed anything much with it yet but I'm sure it will be much better than the 5.3L. However, I didn't have any issues towing my open trailer with that either as little as I needed to.

My mileage with a lot of highway and granny driving is >17mpg. That's not that bad really. I'd get maybe 18.5 with the old truck under similar conditions. Considering the extra weight and much larger engine it isn't bad at all. I think it is comparable to the same truck with the new 5.3L but without the worries of cylinder deactivation.

With the 6.2L you also get the larger rear diff, 4 wheel discs, oil and trans coolers, etc. Most dealer orders come with the 3.73 diff though which I think would hurt MPG some. If you tow a lot it is probably worth it. You can order w/3.42 or go with the Denali which has 3.42 standard. If you price out the Sierra with the Max Tow options it is really close to price of the Sierra Denali which comes with a few extras and interior/exterior styling differences. One example is the "chromed aluminum" wheels on most now are just plastic chrome dipped covers bonded to a raw aluminum wheel. The Denali 20" wheels are still actual finished aluminum wheel that has been chromed or polished(can't remember which at the moment).