Exhaust manifold for: BMW E90 E91 325i 330i Exhaust manifold by TurboWorks, made of 100% stainless steel. Guaranteed power increase of up to 10%. When tuning the engine, the exhaust manifold should be replaced at the very beginning, because the exhaust gases, the cylinder goes to the exhaust manifold, which is part of the engine body, then to the first section of the exhaust pipe, then to the muffler, or several silencers arranged in series, and then to the outlet part of the exhaust pipe. The kit includes a set of gaskets. Outlet: 50mm Exhaust windows: 36mm We provide a 24-month warranty for the product. We also offer lambda probe adapters that eliminate the catalyst error. Additional accessories are also available for exhaust manifolds: Lambda probe adapters Thermal tapes Exhaust manifold intended for: BMW E90 E91 325i 330i Exhaust manifold by TurboWorks, made of 100% stainless steel. Guaranteed power increase of up to 10%. When tuning the engine, the exhaust manifold should be replaced at the very beginning, because the exhaust gases, pressed from the cylinder, go to the exhaust manifold, which is part of the engine body, then they are directed to the first section of the exhaust pipe, then to the muffler, or several silencers arranged in series and then to the exhaust part of the exhaust pipe. The kit includes a set of gaskets. Outlet: 50mm Exhaust windows: 36mm We provide a 24-month warranty for the product. We also offer lambda probe adapters that eliminate the catalyst error.