For just the "basics" on top of stock SH4, you can't go wrong with THEBERBSTER's re-working of of Webster's Game Fixes Only (GFO) mod is really good, and easy
All In One Beginners Mega Mod List For SH4, but I do not think it has the shell casing sound... that, if I remember, is part of Real Fleetboats, but also its own mod somewhere here...