Limited-Slip Differential

A limited-slip differential from Quaife, OS Giken, or Wavetrac transforms corner exit performance by distributing torque to both driven wheels, eliminating the wasteful spin of an open diff. This provides up to 30% more effective traction out of turns, as it reduces understeer and torque steer in FWD cars like the Civic Si, where lap times often drop by 1.5 seconds on a 1-mile course. Compared to Big Brake Kit's big brake kit, which focuses on stopping consistency, this mod directly boosts acceleration by allowing earlier throttle application—common data show a 15% improvement in corner exit speed. On a track, the LSD reduces tire wear by 20% by minimizing wheelspin. While it costs $1,000-$2,000, it's more impactful than a short-throw shifter for lap times. This mod separates cars that understeer into guardrails from those that rotate on command.