Do you know what suspension package you have? 2005 had a few different options, premium smoothride, autoride, Z71, etc. I had the premium smoothride which consisted of wimpy coil springs and giant Nivomat shocks. I didn't like the wallowy feeling, especially at freeway speeds. I bought some Moog Z71 springs and Bilstein shocks, vast improvement. The Z71 springs did lift the rear end a bit, but as I tow regularly I didn't mind the extra height. It is still smooth but much more stable.
This may be helpful:
http://www.shockwarehouse.com/news/g...on-decoder.cfm