I'm at 10psi on my 2011 5.0 M6 with Roush mufflers. Yep, it's loud at WOT, but I don't mind it since the bite matches the bark. Anyway, GT500 mufflers are a good option for someone who wants to quiet down the exhaust.
Yeah im still looking for gt500 mufflers.
What supercharger setup do u have and what numbers did u get on the dyno with 10psi. Im curious