Klenger just said some very wise things, read it twice. I tow mostly at lower elevations. Even the bigger hills i hit (questa on 101) arent that high up. I will tell you this, i can tell a huge difference when i do go up in elevation. My truck is basically a pig. If i lived at high elevation and did a whole lot of heavy towing, i too may need to think about the 4. 10s, oh yeay, i would probably go with stage 2 injectors over 3's if i lived up in th hills also, just too much smoke up their. Man am i glad i live at sea level. Its just so much more fun
