You should not believe your suppliers over exaggerated claims. If it can actually measure 140A per side, you will be very lucky. If you can’t measure the current, you can’t drive the motor at such currents, no matter what the mosfets are rated peak Amp wise. It’s a matter of the shunts, not the mosfets.
We recently tested a 200A continuous rated clone device and it could only measure 120A reliably.
Mosfet wise 200A would be no problem, but the shunts would simply not allow to cope with that Amp flow.
VESC based controllers are not voltage controlled ESCs with no control over the current! Overrating a VESC based ESC is sort of stupid, since it is a current controlled device that would throw an ABS over current fault and would simply cut out if you exceed a safe max peak current rating. Safe means within a region where you can actually measure the currents reliably and precise enough.
Overrating potentially makes users go beyond a safe max current level and that means they are potentially put to danger. If the motor commutation goes wrong during high power drain, a wheel can actually block at full speed.