The barebones racing beast McLaren P1 GTR is ready to go head to head with any rival. This lightweight 7-speed V8 with batteries is a track-hungry monster that you can't take on the road.   

Of course, if you want to go on the road you can always have the panels removed, or put them back on... or even take them off again, it's your choice, as long as you've got the millions to back the changeovers.