Matt- And your a nobodys perfect

Dave- Yes thats it.
Reason? Inertia will be a bit off it (hence rollerbearing turbos), as will airflow causing it to stall (hence in "theory" part the reason for DVs, to stop the air coming back out the turbo when the throttle closed which could slow or stoip the turbo, in "theory"...), but i dont think thats all or even the main bit, its mainly to do with a more modern design, but fuck knows what that is exactly...