Why not fit a scrapyard recon box if you are going to sell it anyway. Me thinks you are still quite attached to the car
Yes Prince - in my totally impartial opinion the A3 is a good option. The 1.8T has to be one of the most tunable engines around - it is the same engine as found in the Golf, Skoda and Seat so there are a few different options around. If you are after reliability the Honda 1.8 Vtec engines are good. You might also look at a prelude, and the Nissan 200sx Turbo which are reliable and easily modded. But overall I would recommend and A3.
HDi will be along soon and recommend an oil burner of some description so hurry up and buy the A3 that you wanted.
Seriously though the A4 2.5TD Quattro is a nice car which is pretty economical.