TRUE..!!
TS, I've experienced in 2 of my cars: kembara & kancil (L5 efrl turbo).
In my kembara's case:
using RON 95 (any brand), when driving @ constant speed of 90kmh and above for more then 5 minutes, engine suddenly choke and flooring the pedal make it worse that the engine will die while moving..even turning the key to start also wont help and i have to free the gear and slowly move to the side of the road and wait for around few minutes before i can start the car again.. at first i tot this is surely engine problem but once during a long journey, i tried filling in ron97 fuel full tank and the problem nvr occur. i tried again filling ron95 when tank almost empty and as expected, the car choke again..so now, i only use ron97 fuel and that surely trims my pocket even more.. only occasionaly i fill in ron95 (when pocket almost empty)..

My kancil's case:
using ron95 (any brand), when accelarating, the engine shudder/jerks causing a non smooth acceleration.. but no engine die problem as my kembara does. using ron97, no problem occurs.

My hyundai (getz):
no problem using ron95.. just abit sluggish that's all.. as expected.

so, for those having similar problems as i am (engine jerks n die), try using ron97 for a change.. that might solve the problem..