This part is listed by BMW as BMW part number 11627833278 (11 62 7 833 278) and is described as the gasket between the exhaust manifold/header and the cylinder head on S85 V10 engines in E60 M5 and E63 M6. These are sold per gasket so order 10 for the complete engine.
This is an OEM manifold gasket manufactured by Elring - the original supplier to BMW for this part, as well as many other gaskets and seals. As the OEM it meets all of BMW's original design, fitment, and performance requirements and is TUV approved. OEM parts are the best alternative to more expensive Original BMW parts because they are virtually identical without the inflated price tag. This part has a two year warranty.
E60 / E61 (04-10) > M5
E63 / E64 (04-10) > M6