Why?
And why only rear engined cars ?
When a rear engine car corners, there is a threshold that when you go over, the handling abruptly goes from under-steer to over-steer, and you "spin out".
A turbocharger has "turbo lag"...This is the time from when you step on it to when the engine starts delivering the power. As a result a driver can accidentally put too much power out while cornering and aggravate the over-steer and spin out....badly.
Google "Porsche turbo 911 widow maker".