My vote is the Zonda R. Unless you're the purist who loves driving the cars on the tires on which they arrive, you'll likely be slapping some grippier tires on either of these beasts for most events - online or off. I know that my vote is based on only two or three races in each vehicle, all of which took place at the Ascari 10-lap challenge (Super class event). The FXX really impressed through the mid and low speed corners. It's stock suspension (or one of the racing hard or soft preset-purchased suspensions? can't remember) really suits it well. I have a hard time resisting adjusting suspensions, and I found that the FXX remained a joy - though certainly a spirited handful - to drive particularly in the many very low speed corners at Ascari. The Pagani didn't seem to give me as much feel of the road - particularly when nearing the moment of grip loss during corner exit throttle application (a likely source of consistent frustration for those with little patience for no-aids-MR-beast driving). Most of my driving was done on Sports Softs. I tackled that 10-lap event with consistent, ginger use of the throttle. Though they are both MRs who tote massively torque-producing engines, I think the Zonda R will hold my attention and devotion for longer. It stands apart as having a greater range (higher) for springs adjustment, and it boasts wider ranges for downforce front and rear (the FXX's aero is static -- cannot be changed, right?). Still, Cards Against Humanity and I think it bears repeating, "Betcha can't have just one."
Also, I'll never forget my first attempt at the 4 Hours of Nurburgring in GT5. I went with a Zonda R on Racing Softs without much (any?) testing or warm-up. I was thinking that I'd get way out in front after two sets of tires, and then just mess around - maybe even heard the other competitors in my rear-view like sheep. I learned quickly that with Racing Softs on a stiff Zonda R meant DO NOT LET EVEN ONE TIRE SLIP OFF THE TARMAC OR CURB. If that ever DID happen, it was a consistent recipe for an irritrievable spin. But in the end (and on Racing Hards - which you CAN slip onto some grass with the tiniest stabilizing throttle and emerge alive), that 4 hours with the Zonda R taught me how to feel for rear traction through the wheel and more competently drive mid-engined supercars.
