They're great cars and I recommend them to anyone. They're not all that powerful from the factory, but have enough power to have a little bit of fun with. They're extremely comfortable and drive like a dream.
Just as Packie offered, I would be willing to take you for a ride in mine once I get it running right so you could feel how they drive.
Nothing wrong with going the NA-T route, that's what I'm doing with mine. The GE motors are pretty stout, and do not require "major surgery" to get decent power out of. A headgasket swap, fuel pump, and bigger injectors is all that you need. The 320whp that you listed is a pretty typical # for NA-T cars running on the stock HG and fuel.
It's not otherworldly to see mid 400whp numbers or more out of a GE motor with the HG swap, upgraded injectors, and upgraded fuel pump. The biggest weak point with these motors is the head, but they wake up very nicely with a set of cams.