question about the stock BOV on a MKIII Turbo

[TehEl1te]

Hey guys, I am relatively new to these cars but I have done a fair amount of research. I found a 90 MKIII Turbo I want to get. I test drove it... it runs like a top, no issues at all, just needs new power steering pump soon which he has so I just need to install that. My question for you guys is, is it bad if the bov kind of chatters? its the stock bov on stock boost but it doesnt have that single hiss release sound, it has like a chattering.

Here is an example at 12 seconds of this video.

http://www.youtube.com/watch?v=_cT2u3upZOs

Is that bad? I was told there are 2 different types of BOVs. Thanks guys!

Oh I am not asking simply because it might sound cool, I just want to know why it does that and if it is bad, how to fix it thanks guys!