ok. i know that the greddy evo sounds nice and it's quiet. that's what i like...but would installing it after i already installed headers make it louder?

Well, Indirectly Yes, since performance increases speed/RPMS, your rpms
will go up faster, thus creating a louder noise, since there is more air flow.
Also, more exhaust flow = more vibrations from the air flow, thus, louder noise.

Car with only exhaust @ 5000 RPM
Headers/Exhaust @ 5000 RPM

Of course, the Headers/exhaust @ 5000 rpms will be a `little' louder, more air flow
and vibrations. Not that much difference.

What you need is the whole power flow -> p-flow, headers, full cat exhaust for the
nicest sound you can imagine :)

But loud is a harse word, I'd have to say more `bass' .. more `hum' especially :)





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