That's a pretty power curve! Funny, my engine smokes big time going down hill, too. Apparently it was re-rung along with new heads about 8k miles ago so I've got some investigating ahead of me (100k on engine). I was considering MS2 earlier today for my 911sc as I'm about to install it on my 90 535i, maybe in the future :D

I once had a boss that told me blue smoke on decel is "suck-by", opposite of blow-by.