Both cars are prepped up to be slightly different in terms of what market they're trying to aim towards. The BRZ appears to be more stable thus less steering input is required. I'm thinking this setup is very good for high speed corners. I still don't like how much understeer seems to be dialed in. This might be for safety reasons?
The GT86 is very fun looking, yet still pumps out a pretty fast time compared to the BRZ. I'm thinking this car is setup more towards the
neutral side compared to the BRZ, but requires faster steering input to catch the car while going fast. Either way, I like how both cars perform. With a set of brake pads and fluid, both cars should be a blast to drive. Besides, all cars fade their brakes on the track with OEM equipment. Be smart and get good track pads and DOT4 fluid.
Having some good tires like the Dunlop Z1SS, Hankook RS3, Bridgestone RE11, or Advan AD08 would certainly spice up the cornering ability as well as fun factor on track. Heat is going to destroy those Prius tires! Don't forget tire pressures play an integral part on how the car handles as well!
Also, Nakaya is a great driver. Time will tell as to what refinements Toyota and Subaru will make to make this car even faster around Tsukuba. As everybody knows, balance (suspension/tire setup, aero, and lastly, power) is more important at Tsukuba than other tracks.