Regarding the sound... i didn't feel much difference if installed inside the plenum, but the type of intake air filter used also plays an important role. If using HKS mushroom filter, I think the ITB roar will be louder. I myself using Apexi dual funnel, sound wise not much difference after swapping out the rubber OEM trumpet to SS trumpet. However, remove the plenum and you will be an immediate crowd pleaser. ;)
Trumpets aka velocity stacks doesn't necessarily increase HP, its more of a responsive improvement thingy. Just to note...
Trumpets aka velocity stacks doesn't necessarily increase HP, its more of a responsive improvement thingy. Just to note...