^My Departure II Pro (3.35") rattles my whole house . It has also set off a car alarm on the other side of the carpark. lol
It makes a very deep sound which I like.
 
Departure II Pro sound:

The HKS, Greddy, Phoenix Power (Departure)  etc dual exhausts are actually quite acceptable volume wise mated to a factory down pipe. 3inch downpipes & less restrictive cats (or none at all) make them significantly louder. Fujitsubo is hands down most quiet even with a bigger dump. The old hi-tech MR2 exhausts are quiet too.

Fujistubo is the quietest 3" aftermarket bolt on brand name exhaust.
 
The apexi super megaphone is quieter still, but its only a 2.5" exhaust.