I'd go for a Subaru Legacy or Impreza, of course I'm biassed as I own a Legacy
You would be able to run the DeltaDash ECU monitoring/programming software.
The other reason to go for the Legacy it looks and is specced similar to cars 3 times it's price. I regularly get accused of owning a BMW 3-series or an Audi or a Lexus. A highly functional car computer built for half the price of an OEM car computer, or Pioneer cd/mp3/dvd/satnav head unit seems like a perfect complement to this vehicle. There is also tons of space behind the dash, mine has a triple DIN (though official UK ones dont, YMMV)