You have an '06, I have an '07 not much of a difference. Most leveling kits are the same, just a spacer... They come in steel, aluminum, and plastic... Stay away from the plastic... I preferred the painted steel type... Brand names are not significant go for the best price... I picked a 2" leveling kit and my truck is almost totally level... I think this image shows it's level...
Regarding my Ti, it is the 1ghz model, I do switch the 15" and my 17" PowerBooks in my truck... They both fit it just depends on what I'm doing...
It does come in handy...