Im fairly new to the mod scene on my 03 cobra and im confused on the pulley scene. I hear so many differ sizes such as 2.8 2.91 what is best? and whats up with the lower pulley? 4, 6lb? I have no idea about either of em and am looking for the best, safest and most efficient way to go. What tools and parts will i need to have to install and get the process done? Will i need a tensioner? If anyone can pretty much help me with what exactly doing a pulley swap with a "Lower" install? i am just new to it and would appreciate any help. Thanks