Whats the difference between the Pagani Zonda R and the Pagani Zonda F?

the zonda r has got 750bhp while the zonda f has only got 600bhp





and the zonda r has got a completely differant back end compared to the zonda f|||Despite sharing much of the Zonda's shape, the R CS is almost entirely new, sharing only 10% of the Zonda F's components. It has been obliquely suggested by Horacio Pagani that this car is a testbed chassis for certain components of the Zonda's replacement (in the same vein as the Ferrari 288 GTO Evoluzione and the successive F40) and that the R CS accurately reflects some of the Zonda's successor's features.