hmm, when i drove it i found it pretty cramped, if you have a passenger in the front seat thats 5' 11' or above you cannot sit a average adult in the back seat there simply isnt any room for any journey more than 15min, yes if you are only sitting in the front, or only travelling in the back with no one in the front pasenger seat then there is reaosnable room. compared to a latest gen corolla, the corolla is a good 8inches longer with a longer wheelbase which is a huge difference. a3 size can be compared more towards a honda city but a3 is wider so its slightly better than that.
compared to other german cars it still not wide enough and driver and passenger elbows can touch which is not the issue in C class, or 3 series or higher up models. that said for the price overall package of a3 is great, just get the a4 if you want a audi and want to carry family and kids in comfort for logner journeys as a3 is very small.