Some engine's will not run with bov so that sorts it for a majority of people. Me personally I like them I don't care if people think its a chav thing I know blokes closer to 60 that have them. And good on them I say. [emoji106]
Truth is there is no statistics that prove there good or bad they certainly don't increase anything but might increase the life of a turbo. I like the noise when I change gear lets people know its a turbo but if my car couldn't run with one I'd just take it off.
I have a baileys but prefer the sound of a hks. Just gpt to be careful of fakes. But if you're thinking getting on either borrow or get one of the £25 ones to test it 1st. Only advise in my honesty I can give lol [emoji6]