Originally Posted by JIO
With 10 individual throttle bodies, one or more may be rattling a bit as the air enters. It's probably doing it in all gears, but you can hear it better in the lower gears when the tires aren't drowning out the rattle sound. As long as there is no surging, I wouldn't worry about it. If it continues to bug you (it would bug me but I'm OCD...he he) see if the service people can hear it.
Hes right. It could be the sound of 2 extra throttle bodies screwing everything up.