A top-mount turbo exhaust manifold/header for the BMW N54 engine (E82/E90/E92/E89), designed to relocate the turbo to the top of the engine for a single or twin-scroll conversion. Kungfu Performance and similar Chinese manufacturers sell this style of manifold on AliExpress/eBay in thick stainless steel; a directly comparable listing of the same part type ("N54 Top Mount T4/T3 Single Turbo Exhaust Manifold for 135i 335i 535i Z4 E90 E91 E92") ships with mounting studs, nuts and gaskets but without wastegate provisions.