This Ferrea Dual Valve Spring Kit is an endurance-spec upgrade for the Subaru WRX STI (EJ-series), designed to maintain consistent valve control and resist load loss under sustained boost and high rpm. Sold as a complete kit.
| Type | Dual valve spring kit (endurance) |
| Application | Subaru WRX STI (EJ-series) |
| Use | Endurance / boosted valvetrain upgrade |
| Part Number | KT4020 |
Shipping: In-stock orders placed before 3 PM EST ship the same day, and everything else ships within 24 hours. Standard, expedited, and overnight options are available at checkout. Backordered items ship as soon as we get them back in stock. Contact us for lead times. See the full Shipping Policy.
Returns: 30-day returns on new, unused items in original packaging. See the full Refund Policy.
