WhaItDo

I'm looking for some opinions, and i'm wondering if you can help. I'm looking to buy a car, and I'm thinking about purchasing an Audi A4 1.5 Turbo--it is in my price-range, stylish, and equipped with some things that would make my driving experience a lot more enjoyable (I currently share a 2006 Honda Civic with my sister). I have a found a few, but want the opinions of a few guys (or girls) that know their stuff.

How reliable is the car? --> mostly the engine... i'm going to buy a used car, but besides its history how reliable is the engine, and how well should it be maintained.

How expensive are its parts in comparison to a more generic brand of car (i.e. honda or toyota), and how often, in your experience, have you had trouble with your audi and needed to replace its parts.

What type of gas does it require (unleaded, premium, or supreme). Is any which one necessary for its maintenance?

As this is my first car, how should I maintain my car to maximize it's lifespan?

Cheers.

D