If you're not going the Supermod route Webster's mods are great, and he says 1.4&1.5, so you're gtg. Reduced planes is a must, SH4 was nearly unplayable before I added it, although I have 1.5 so I'm not sure if it's the same for 1.4, so get this one:
http://www.subsim.com/radioroom/down...do=file&id=473
Don't forget JSGME for easy mod enabling/removal.
Otherwise just play it for a bit, develop a feel for the game, and discover what really irks you, read some books on Subs to gain a historical understanding, your local library should have some, I especially enjoyed the Time-Life one, as well as
Thunder Below. Once you know what bugs you, and have mastered manual targeting, you know what you want to fix, and can search accordingly.