First off I want to say I love Mustangs....have had Mustangs all my life until 2001 when I got into my first BMW E46 M3. The problem BMW M3 owners have is that Ford actually sells go fast parts for quite cheap that are CARB legal and come with a factory warranty. Case in point..
http://www.fordracingparts.com/parts...KeyField=12168
This S/C kit is available from Ford Racing Parts for under $7K and is CARB exempt and it has a 12mos. warranty with it as long as its installed by a Ford dealer.
As far as NOS on a Mustang there are some people who do squeeze them but you are taking a chance as one hiccup and you destroy the plastic intake manifold from the backfire.
That is why I wish someone like Gintani, VF engineering or someone else who makes blowers wish they would get these things CARB exempt.
Dave