My other car is a MINI!!!!
No, I didn't say the A3 is a waste of time at all.
the 1.6 A3 is gash. utter ****e. It's an old 8v engine, sodd all power, and not very efficient either, hence it's poor economy and poor power.
The 1.8T is much more modern, and despite developing much more power, it'll give you just as good, if not better mpg than a 1.6 8v.
The quattro system is fat and heavy. This coupled with the lower power of the A3 is crap. The weight makes it slower. The weight makes it less economical. No upsides to that one.....
The S3 has more power, so goes well, but it's still heavy, so economy isn't that good.
the FWD A3 1.8T however, has decent power, AND low weight, so it's fairly quick, and still fairly economical, making it the most sensible choice for an all round, economical, reasonablly nippy car.
Basically, don't buy the 1.6 A3, it has NOTHING going for it. the 1.8 T Quattro is a bit lost, the FWD 1.8T is great, but if you want that bit more class the S3 wins it.