Has anyone replaced the hose that goes down the center under the manifold? It looks as though the supercharger has to be removed?

I’ve basically decided since it’s a 2-3 hour job pulling the s/c I’m doing everything that can be done. Valve cover gaskets, knock sensors, new pulley, rebuild the snout, have the s/c checked for clearances and rebuilt if needed, all hoses, and since I already removed the throttle body I’m gonna strip it down and thoroughly clean it too.

Replace the part load breather tube while you’re under the SC. It will be extremely brittle and will probably crumble when you touch it, but it is plumbed to the intake elbow under the throttle body, and you will have a massive vacuum leak if you don’t replace it, even if it looks ok. It happened to me. In my case, I was able to replace it later because the line does not HAVE to run under the SC, but life would have been simpler had I just replaced it while I had the SC out. Also clean out the port where the part load breather tube goes into the engine in front, using a small drill bit, held in your hand. Do not drop the drill bit in the engine! I clipped a small vice grip on the drill bit to be safe.

Might as well change the SC oil while you have it out.

One other thing you might want to consider.
Brass insert on side of TB elbow. C2S15816
You won’t need to replace the brass itself but, the o ring inside along with the plastic retaining clip most definitely will need replaced.