As nice as it is to visit a reputable tuning company such as a Titan Motorsports or Heffner and drive their creations, I'm never really surprised by them. Everyone says their cars are fast as hell and run great, and then when they do, it's exactly what I expect.
On the other hand, when a 23 year old kid tells me he built a 400-horsepower E30 BMW in a shed, not by swapping in a V8, but by designing, building, and tuning his own turbo kit, I'm interested. I'm especially interested when he tells me he's been developing the car at the track and on the autocross pad over a period of 7 years, since he was 16. Then, it all gets better when you drive the car and realize he wasn't just blowing smoke up your ass: it works exactly as advertised.