Hi sifus,
How much "real" difference will I be able to see with a
Zotac GTX780 Ti Amp! with a
"standard" GTX780 card? I'm seeing some replies here saying the standard GTX780 going as low as RM1670 which is so much cheaper than the Ti Amp! version which is around RM2300 (savings can go to a better processor). From xbitlabs it seems to be about ~5FPS difference on the few games they tested.
I'm not sure if the Ti Amp will fare better with newer "next gen" games or the performance increase is negligible. Maybe you can advice to spare me any potential regrets with skimping on the card now

Also @Zgames I've modified your recommended build slightly based on
Logical Increments Guide for a "balanced" build (others who are looking to build a PC, check this out too, the site is really helpful)
Proc -
i5-4460 i5-4690 or i7-4790
Mobo -
ASrock H97 Pro4 ASrock H97m Pro4 (I want to fit this inside a Micro ATX)
RAM - 8GB Value RAM
PSU - Seasonic S12II 620w
GPU - Zotac GTX 780 Ti AMP! or "standard" GTX 780
HDD & SSD - recycle
Casing - maybe bitfenix or fractal design 1000
To recap, I want a gaming rig (only) that will allow me to max out graphics and as future-proof as possible within a RM4k budget +-
Any critique / comment to help me fine tune and finalize my build is very much appreciated!

780TI is a different cards from 780.
Nope, cheapest i5 should do what the pricier i5 can do in gaming too, no much different. If want go pricier, might as well look at Xeon, near i7 performance at near i5 price (RM780++).