I just got tuned and I am hearing what I think is turbo flutter. It is really only doing it at low RPMs driving through the neighborhood. I read some people say it bad, some ok. Is it bad for your turbo and would a blow off valve reduce or get rid of it?
As mentioned, you shouldn't hear any flutter with the stock DV. I've heard some aftermarket BOV's are known for it, but generally speaking, a flutter sound is bad. Check your DV to make sure it's not seized or sticking, and contact your tuner asap.