1989 G50 build with CMS Forks Calculates shift points, RPM drops, missed shift RPM based on gears and tires, in MS Excel format 915 Gearboxes (72-86 911) G50/G64 5 Speed Gearboxes (87+ 911 Carrera, C2, & 89 turbo) G50/G64/G96/G97 6 speed Gearboxes (993, 996turbo and 996/997 GT3 Street and Cup) Generic