Diesel exhaust sound

[DI48LO]

Okay, I found out how do they get the sound I'm talking about. Sorry, I have no video, and I can't found one on youtube neihter. You have to belive me, it's a great sound, and nothing like a blow-off valve.
In case of a 2005 Astra they replaced the turbo with a variable one, and emptied all the mufflers and emptied the cat too (not replaced with a tube!!!). So this modification has any negative effect? Other than emission...