There is a long discussion on the other forum about this very topic, here is a small recap:
I feel a difference, butt Dyno
Don't buy if just looking at hp/TQ gains, lot of disagreement on if and how much you gain.
I like the slight increase in noise and gurgle sound when coasting.
Lower pressure out the back can mean slight reduction in spool times which would explain increase in TQ at start.
I upgraded intakes and my intercooler, for me adding these made complete sense as is part of my larger plan.
My opinion
Worth it, yes
Do it for HP/TQ gains, not as primary reason
As part of a plan to open up air in and air out, yes!
By way I did line my entire trunk with sound deading.
Hope that helps
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