Geesh, what kind of connection do you have. Even the largest mods shouldn't take more than 30mins on basic cable.
I agree with most, comparing stock to SH3 with mods...no camparison. You think stock has decent graphics...wait until you load a supermod, all have enviroment mods that improve graphics 100%. A mod like TMO changes the game 100%, then the other great mods. A recent mod just came out that gives us a working radar and TDC.
I played SH4 stock for a week or so and shelfed it. About another month came to the forum and found mods. I've played it nonstop since.
Haven't played UBoat additions in months, but OM is a great mod and many others..It's fun sinking those big US ships.