Swift Round Wire Linear Rate Bump Springs 400 lbs/in Metric Coilover Springs The increase in spring rate

The increase in spring rate is based on the upper limits of the vehicles factory shock valving

3" B-pipe to dual 3" muffler

and adds improved handling and lower ride height for driving enthusiasts and style minded drivers who demand only the best

Supports both twin turbo N54 and single turbo N55 BMW 135i variants

Best flowing & sounding exhaust on the market today

Swift Round Wire Linear Rate Bump Springs 400 lbs/in Metric Coilover Springs The increase in spring rateRound Wire Linear Rate Bump Springs 400 lbs in Swift Bump Springs are made from a proprietary material. The same springs are used in Super GT, Formula Nippon, F3, F3000, Super Taikyu, IMSA, Pirelli World Challenge, Rally America, VLN, Le Mans Series, Formula Drift, and many other professional racing avenues.