Thermal barrier coated using High Performance Coatings (HPC) Hipercoat 1600+ process on the inside and outside of the header. The Hipercoat process helps maintain high exhaust gas velocity which is key in header design and ultimate power production. One of the few 304 stainless & inside/outside ceramic coated headers in the world. Uses large port 50mm primaries & high flow CAD designed 63.5mm collector (2.5″). Perfect compliment to the Berk Technology 2.5″ test pipe. Includes secondary wideband O2 sensor port for fuel tuning. One of the best performing headers for the AP1 & AP2 S2000 at any price.