Besides an auto ’box ($2000) and heated leather/Alcantara seats ($1500), the BRZ is essentially a one-size-fits-all proposition ... until you become aware of its vast cache of dealer-fit accessories. Ditto the MX-5 RF, with an auto ($2000), premium paint ($300) and black roof/tan Nappa leather combo ($1000) its sole options. The Cayman S, on the other hand, is a blank canvas. Our Lava Orange ($5390) test car included Sport Chrono package ($4990), sports exhaust ($4330), torque vectoring with locking rear diff ($3190), carbon interior ($2890), 20-inch Carrera S wheels ($2710) in high-gloss black ($2890), Bose stereo ($2650), park assist with rear camera ($1690), Connect Plus ($1090) and GT Sports steering wheel ($660).…