couple questions about turbo chargers

hi i was thinking of getting third generation supra, possibly the turbo model and i had a couple of questions about turbos and the supra

1. is the turbo on the stock mk3 supra considered to be a large one? (i know this can be a bit subjective)

2. since the turbo increases the amount of air and fuel that goes into the pistons, does the turbo use a lot more gas? like, does it drain gas like no other? or do you not notice that much of a difference?

3. and do you have to use a higher octane fuel to prevent knocking? would regular just not work?

thanx in advance