so which would be a quiter and most efficient(horsepower) low end to mid range combination of header and exhaust? comptech,dc sports, apexi or Greddy? and what model?

way too many choices out there and i dont know which one would look best on the teg.

Also there are one piece 4-2-1 and two piece 4-2-1 header, whats the difference? and which one is better?