As someone who touch-types Dvorak at home, and has to switch back to QWERTY at work, I think I can safely say my experience trumps your few symbol keys moving around...
Why aren't you using Dvorak at work? I use Dvorak at home and on my work computer as well.
And 600HP is nothing. I've got a good friend from college who gets almost 1200HP in his GTR (1192 WHP / 1402 crank, actually). I don't see him wrapping it around vertical objects.
The GTR (unless you are referring to the Ultima GTR) is front-engined and all-wheel drive. One with 1400 hp probably has a tremendous amount of turbo lag as well. I really don't think you can compare that to the mid-engined, naturally aspirated V10 Carrera GT.