Sorry to dissappoint you, but the Aerial Atom is like 60 Grand. And I think you mean a supercharged Ecotec- Civic engines are high compression and do not respond well to anything but Vortech superchargers unless you are willing to do some internal engine work. A Hayabusa does this better for less- if you like driving motorcycles.
In a nutshell, Carrera refers to the standard 911. The H6 is tuned to about 350 Hp in the current generation. Turbo models make about 420 (997's make 480) Hp. In terms of trim, the Carrera has the softest sprung suspension and Continental tires allow for a quieter ride. Also, there is more sound deadening. In the Cabriolet, you can expect much more noise, even with the top up. To contend with the extra weight, the suspension is stiffened. With the Turbo, you can expect an even stiffer suspension and more tire noise, but still a decent amount of deadening. All levels should offer stuff like maybe nav systems, heated seats if you're into that. But Porsches are definitely bent towards performance instead of luxury.
I think you're best off with the Cayman. Porsches don't have reliability issues most of the time, but overall the Cayman is a smoother, less bulbous design. It's my favorite, but by no means is the other 911 bad.