A body lift won't change the nose down stance of the truck, it will just be nose down a little higher in the air. The only way to remedy the nose down is with a leveling kit (struts or spacers) for the front suspension. Depending on your dealership, the warranty on various front end components might be compromised. There have also been some issues with a "wobble" in 4wd after a leveling kit is installed. It is really hit or miss as to whether a truck will wobble or not, mine does not but I have heard of many that do.