If its added to a non-LSD car, its STX. Only cars equiped from the factory with a viscous LSD are allowed in STS.
No limited slip differentials are permitted except for factory standard viscous coupler type units.
2003 Ford Focus ZX3 2.3l N/A = 221 HP, 162 ft-lbs, email@example.comMPH - SOLD
2006 Ford Fusion 2.3l Turbo = 244HP, 247ft-lbs
2016 Ford Fusion Hybrid