BLUF : you CAN use regular in a pinch - it's just that you'll have to decide how long or how far that pinch is. These engines will likely adjust their "tune" themselves on the fuel you put in it - at least to some degree. And that degree is also a matter of range - the range of adjustments.
Now for a bit more (but not too much more) depth : there are a few different ways to make these 'adjustments' , anti-knock sense of timing advance, fuel rail pressure to a/f mass, etc. and the tuner boxes both at the ECU and piggy-back types, take advantage of these to maximize power against fuel - remember higher octane is slower burning, but with with more consistent flame propagation at higher compression - so has more kinetic energy/mass - hence a bit more air = a bit more power (so long as the REST of the system can accommodate - carburetors can't, but today's TFSIs CAN).
Quite simply, the reverse is true too - you could prolly expect your 200 hp Q3 to run at 180 hp under regular gas, but prolly not much else to go "wrong" - ditto the 220 hp version (and not merely a like or proportionate percentage, but prolly also the same - absolute value - 180 hp). This is true because the 220 hp version is likely just a bit more tuned up and WILL require the higher octane with more consistency and expectability (not sure if that's a real word, but my wife thinks my mission to 'create' prolly isn't so good either...) even to make its 220 hp.
hope that helps a little - but I cannot take responsibility to recommend your choices - 0