So here's the deal...
I'm looking to buy an S40 T5, and I wish to have a BOV installed...

The sound I like the most is the "Chatter"... But from what I've read online, the chatter is the sound of an engine that is not healthy?
How to describe a sound in letters... The "Fthhhhhh" is cool, but the "Frrrrrrrrrrr" I like more...

Would someone explain to me the pro's and con's? And please let me know if a "normal" dump valve is better?

I have NO experience with turbos, so...

Since I'm gonna spend 50.000+ $ on a used car, I would love to hear your opinnion...

 

The stock turbo has a CBV which does almostthe same thing as a BOV.
BOV vents to Atmosphere, while the CBV vents back to the intake manifold.
HKS, Forge, and Greedy have some nice options.
I think MOPAR has a plate you put between the CBV and the turbo which makes it sound like a BOV.
If you want to here the stock CBV buy the plate from MOPAR or put an aftermarket intake, cone filter or K&N replacement filter.