The only thing I can attest to is that the V3 is louder than stock since I have no experience with other after market systems. I've had it a year and a half now and remain a little perplexed of the many comments stating the "V3 is too loud". Well ..,it isn't, at least from my point of view.
Some recent posts seem to also suggest that the V3 will upset and even wake-up the neighbors. I don't think this is true at all if your not high reving the engine backing out of the driveway. High revs with the stock exhaust could just as easily bring the same complaints.
Well, so it goes. My weekly(so it seems) defence of Invidia. Anyone truly concerned about noise should just stay stock.

 

 

I purchased/installed the V3 last weekend. I love the sound! Couldn't be happier. deep and throaty! and WOT throttle burst are even better!