Hey zblue
i was thinking about your question since 1 week
i'm confused
the borla exhaust give the best power ever comparing to any 350z exhaust (it gives between 16hp and 20hp) this is the borla advantage
in other hand the nismo exhaust give u marvels sound
it's realy fuckin damn great SOUND but it give u just 6hp
ok now the showtime u must check out this:
Nismo Exhaust
and this
Borla Exhaust
C the diffrince on the sound
so i choose the nismo exhaust ,this is just my opinion
Peace369out