The optional S/R package added stiffer suspension parts (Eibach springs (M-5560-Z2), Tokico struts (M-18000-Z2) and Energy Suspension brand polyurethane suspension bushings), more power (through a Ford Racing PCM (M-12650-Z2)), more efficient intake (Roush or Iceman), rear disc brakes (M-2300-Z2), a stronger clutch (Centerforce dual friction M-7560-Z2), a short-throw B&M manual-transmission shifter (M-7210-Z2), an S/R-unique shift knob (M-7213-Z2) and boot (M-7277-Z2), upgraded seats, a unique blue valve cover, a different speed cluster that goes up to and a unique tire and wheel package. Engine power was increased 10% over the base Zetec engine used in the ZX2 to , courtesy of a recommended premium fuel re-calibration, new air inlet system, the performance PCM, improved Borla muffler and pipe (M-5230-Z2). All ZX2 S/Rs have a special "S/R" badge on the back, either silver (on a red car) or red (on a yellow or black car). Some S/Rs went out of the assembly plant without some of the performance mods. The suspension bushings were not installed at the factory but instead packaged with the car for installation at the dealership. This also led to many cars leaving the showroom without the full complement of S/R parts.