Add to Cart Compare Quick view STM Tuner Secondary Torsion Upgrade 1.5" bushing ID MSRP: Now: $105.00 Was: STM Torsion spring cover option. Allows the use of a torsion spring with the option of 7 spring load adjustments with one spring. No drilling or modifications to the STM Secondary is needed. Does not come with helix or spring... MSRP: Now: $105.00 Was: Add to Cart Compare Quick view