First thingz first, we need to recognise that the S5 ROM cannot and will not work directly on an S4. Different hardware, etc.
That said, the only way to get a near S5 experience is to install a custom S4 ROM that has been 'dressed' to emulate the S5 experience. No custom ROM is "complete' asis. Some tweaks need to be done by you, the user, via built-in features, or tweaker apps.
If you have absolutely no experience in rooting, or flashing ROMS, do not try it. A wrong step taken during this process may render your phone literally useless (can be recovered sometimes).
OzCan ROM for S4 (i9500) is the one that is stable, gives great battery life, and the near S5 experience S4 users want. Current version is 5.4
