IMHO only good suggestion I've seen so far has been the mid to late 90's Subaru Impreza.
I own a DSM and an Audi, so I can suggest not getting either of these cars. You can run into maintenance problems with the A4. Completely stock, very well taken car of 2g's have been know to crank walk. There's an inherent problem in those engines that make them more prone to crank walk that has little to do with mods except for the clutch. At that point you have a shell that's not worth a whole lot with an engine that's relatively expensive to replace.
The Subaru should be rock solid, get good gas mileage, and be in your price range.