I don't think its been proven that all 6MT, M3's do not have a CDV restriction. I remember seeing some M3 posts last year that some of the later M3's had a CDV! Older M models had them!! I think the only way to really know for sure is to remove your and inspect it. Its not hard to do.
And chances are that your car will have a CDV restrictor and getting rid of it is soooo worth it!
You do not have to buy a new CDV part (from a vendor or bmw dealer). You can also just unplug your old one and plug in the clutch hose with out the CDV. But I wanted that "stealth lool" just in case I had any clutch issues down the road.
I bought a spare CDV from my dealer and used a 3mm punch to knock out the restrictor...
CDV Delete/Replacement DIY