Word is the Superlift shaft will hold up. You can keep the stocker but the U-joints don't like the increased angle and it won't last real long. The front driveshaft spins all the time because the hubs don't unlock.
I put the superlift on mine, but didn't get the driveline. I haven't seen or felt anything wrong. If it does start going out I figured that it would be cheaper to have a new one made at a local driveline shop than to by their's.