I'm trying to gather some info on the pros and cons of a torsion key lift and for a spindle lift. I'm planning to give my 05 Colorado a small lift. I want to give it a slightly more aggressive look and not sure which route to take.  

Key lifts are to be avoided and in my opinion should not even be sold. They throw suspension geometry out of whack and place suspense at of near limit of extension and places more strain on CV's by running them at a higher angle and reducing their torque capacity. (CV's are strongest and last longest when run at lower angles) The proper what to do it is with a kit that lowers diff with new knuckles that keeps half shaft angle correct too.