Even though I've never owned one, I would have to say the most underrated car I've driven was the Ford Focus XR5 Turbo produced from 2006-2011. Far more affordable than the Golf GTi (the hot hatch category benchmark) yet with pin-sharp handling and stunning performance. Its turbocharged five cylinder produced 166Kw/320Nm with an addictive soundtrack reminiscent of a Cosworth BDA Escort. Six-speed manual, hip-hugging Recaro seats and ample room/practicality with its five-door hatch body. A good looker too (click on image to see the whole car). I didn't want to buy a used one because I feared they all must have been driven hard - I mean, how could you resist!