Would love to see your results for this as I travel along these places too.
Eventually I have chance to do the acid test, turn on hotspot for my car to connect to download firmware package (~5GB) while driving from woodlands to Jurong East,
SLE -> BKE->KJE->PIE -> Jurong East.
*BKE/KJE & KJE/ PIE. Both junctions are notorious low coverage area.
During the commute, Google YouTube music streaming ( not downloaded play since my car YouTube music don't come with this buffering technique yet) was active.
No music pause interruption, Car firmware complete package downloaded
So far no disappointment.
Value for money $15 CIS plan. 300GB .