I have heard discussions on people putting blow off valves on the turbo, just for the noise. It has no actual performance increase, that I know of.

I have however discovered by swapping out the stock air filter, not permanently, but with an advaced auto parts air filter, you can hear the turbo chirp, at least on my car you can.

I wouldn't recommend leaving the aftermarket air filter on though, many discussions why you shouldn't, but it is fun to ride beside people, stomp it and let the turbo scream in their car.

I have also removed a bunch of unnecessary EGR vacuum, also, but you might not have to.

Anyways, I just thought this might be an interesting topic, rather than me rambling on about the downs of the vehicles and random questions.

Thanks for all comments, opinions, or thoughts!!