Apexi World Sport is super quite, you only can hear you intake and VTEC....
GReddy Evo is nice exhaust, sounds really good, but if you talking power gain, I would say Apex'i N1 is better then Evo, N1 is designed for racing and performance not for good sound. both exhausts price are pretty much the same, like $480-500. good deal!
if you have $700 bucks, go with comptech or Type One exhuast, both of them is the best best exhaust for integras. IMO