My cousin has the Tanabe cat-back with an N1 muffler. Nice power, but the noise is pretty bad on long drives (gives everybody in the car a headache.) He also has to watch out for speed-bumps.
A coworker has the Evo from GReddy in his Si, and in my opinion, that one is a better all-around exhaust for the street. Not as much power as the N1, but more discreet, and since it's tucked-in, not need to worry about speed-bumps. Good sound too.