throttle sound louder than it should

[SlowPro48]

It's probably just your stereo running lean...

[tom4bren]

Check the clutch on your fan. If that gets worn, it can very loud.

[Cobrajet]

Also, a loose EGR nut can create a louder exhaust note. (But I couldn't hear that over my PV1 catback!)

[blacksambo]

Also, a loose EGR nut can create a louder exhaust note. (But I couldn't hear that over my PV1 catback!)

Ditto on the above. But get a engine code reading. My bet is a #171 and you'll have to change your common chamber gaskets. Torque only to 13lbs. or hand tight max. Keep us posted.