Mod suggestions?

[USAMP1980]

I have been playing SH3, off and on, since it's release. I have never tried a mod for it, and I was hope each person would nominate a single mod which they feel is the best overall mod.

*I think SH3 is a great game, and I was terribly disappointed by 4... although I think 3 could have been much more indepth.
IE: No wolfpacks in campaign, no hint of Allied ultra encryptions of Egnima, no Atlantic wall(s) in proper time frame(s), no escourt carriers on search and destroy missions against U-boats, no historic battles integrated during campaigh (ie: forces you to skip D-day). I routinely sink over 100,000 tons on a single mission in full realism... does it effect anything in the campain? No.

Has anyone created/edited a mod to allow access to the rest of the U-boat (ie: quarter(s), torpedo room, engine room(s), etc. ?

Basically, I believe I would enjoy a realism mod more than something off-the-wall.

Thank you for any input.