You'll be happier with the 5.3! My Tahoe has one, and my work truck has the 4.8. I notice the 5.3 has a lot quicker pickup when you slow down, then speed back up. The 4.8 will get in an area where its not in the power band, causing it to down shift more. Also, if you plan to haul/tow, go for the larger engine. Both get about the same mileage. I think the resale would be better on one with a larger engine also.