From what i have seen with the part installed is this.
There is NVH but its not all that bad. Is see it usually around 2k in the RPM range then it somewhat subsides. I have seen an improvement in shifting with a stock shifter to me is a big plus. I would like to now see this part...
But I could get a muffler shop to weld in a muffler if I chose to. I was think just buy 2 magnaflow mufflers and go with the gt500 tips. Have them cut out the resonators and add everything all at once.
I'm still stock. I'm just trying to get new stuff.
I sold my 06 about 6 months ago. Was in a srt8 jeep, wasn't for me so I jumped back into a stang. Couldn't be happier only problem is the mod bug and moneyzz.