Hi-Po 302 Ti-VCT V8 engine or 5.4L supercharged 4v v8 engine?

Im intending to buy a mustang and i have the extra money to spend. Im looking at a Boss 302 (Hi-Po 302 Ti-VCT V8 engine) and a Shelby GT500 (5.4L supercharged 4v v8 engine). Im not much of a car guy, so i was hoping someone could educate me on the matter of which would be better. All i know is I want it to be fast haha and the Supercharged engine sounds like that would be it but i really dont know what im talking about. Help!:)