I have wanted to add a different pulley to get more than the factory 8lbs of boost. I have heard of a #4 and a #6 pulley. How much more boost do you actually get by doing so? Do you have to replace the belt afterwards or use the same one. I live about 3 hours from Saskatoon which is the closest svt dealer and where I bought the truck from. I just thought I would ask other lightning owners or people who have done the pulley change themselves.