I had the 4.8L in my '06 Silverado, and upgraded to the 5.3L in my '10 Sierra. I have to say that I'm glad I ended up with the bigger engine! I do a little bit more interstate driving (love to travel) and the VVT on the 5.3L has been awsome! Even in the city the little bit of extra oomph from the bigger engine still puts a smile on my face! Overall I'd still say go with the 5.3L, and you won't be dissapointed!