I think the auto has an "advantage" of being a little smoother and less fore and aft space required to install it, so you can fit the tunnel a little tighter. It might be a bigger tunnel in some regards, but with my T56 I needed to leave enough room to be able to stick and input shaft in there and push it forward several inches. You can shoot it in at an angle for a little bit, but ultimately you still need probably at least a good 3" or more that you can pull it straight back to clear the clutch. With an auto I think you only have to be able to pull it back maybe 1-2", if even that. Just one thing to keep in mind when building a tunnel. Don't build it so tight you can't take things back out after you're done. Would be a pain to hug everything tight, get it all tacked together, then you can't pull the trans to do the bottom side cleanup.