Can the mind blowing Porsche Cayman GT4 live with its bigger, more expensive brother, the Porsche 911 GT3 RS, on track? Watch as Steve Sutcliffe finds out on the famous Silverstone National Circuit...

Porsche Cayman GT4 review: http://www.autoexpress.co.uk/porsche/cayman/90790/porsche-cayman-gt4-2015-review
Porsche 911 GT3 RS review: http://www.autoexpress.co.uk/porsche/911/91537/porsche-911-gt3-rs-2015-review