For $30k you can get a lot of cars.I'll ignore the Sports Compact criteria and focus on performance or performance potential for $30k and less.The new Civic Si or Acura CSX are very nice ... I've always liked the WRX for its performance but I would get the 2005 or 2006 one. The new model doesn't interest me that much.A 2001 M3 is in your price range if you want serious performance. But try to get one with the warranty replaced engine.The Mustang GT is in your price range as well and the potential there is huge. You'll need to put in $5k to upgrade the rear suspension to dial down the oversteer, but that's a cheap price to pay for the performance.I also like the RX8 - a 2004 is in your price range. Same with a 2002 Boxster.Good luck.