The best combination of mods for SH4 are for version 1.5. You can use 1.4 and you have some nice mods, but, if you can it, buy the 1.5 - UBoat Expansion You can add to it FOTRSU or Ralles Modsoup (by Bleiente), and you will have a very nice modded SH4.
Regards.
Fitzcarraldo