Wilf - as far as rebuilding or prepping the motor goes, you don't even bother!!! maybe throw a new timing belt in there for the sake of it, but you'll often see reasonably low mileage motors at the Jap Wreckers for $1000- or so. They're all alloy, forged crank/rods/pistons, 6 bolt mains, etc etc. The Japs sure know how to OVERengineer a motor!
The motor in question has a couple of small turbos on it at the moment. It's never had a proper dyno tune, and as a result it's always been tuned really conservatively. A couple of newer, bigger turbos are on the way now. I think Scott would agree that the new combination should be good for an easy 500hp with absolute reliability. If it were mine, I'd go slightly bigger again in the turbo department and throw a bit of good fuel in it. In that trim, it'd be an easy 650+hp motor. Bear in mind that this would be possible in a $1000 motor with totally standard internals, without even pulling the
oil pan off it....