Stay away from the 1.4 engine.

It's stressed, and the turbo is not strong.

The S4 B8 is a superb engine, but it's thirsty as is supercharged, heavy and 4wd.

The S3 is a very good car. Best 4 cylinder engine there is. 8 injectors, water cooled exhaust manifold makes it good on fuel and very very tuneable.

Have a look at the Golf GTi. These are an awesome car, handle better than an S3, and are very frugal being lighter and 2wd. Same engine but smaller turbo. They tune to over 300bhp with just a map and are generally very reliable.

Rick