i read in this forum that the batteries in O3 are either AGM or EFB due to the start/stop technology. 

if i had disabled the start/stop via vcds, could i replace the car battery in future with normal sealed maintenance free wet cells?

Doubtful. You would need to check if the car has got a "smart charging" alternator, if it has, then you would need to stick with the correct battery - it may even need coding to the car when it needs changing as modern cars with smart charge often need telling they have a new battery, otherwise it may not charge properly, or indeed overcharge a new battery.

how do i check if it has a smart charging alternator?

 

 thanks for the reply :)