Mahle
Mahle has been manufacturing high quality products since 1920. Mahle is one of the largest manufacturer of filtration products in the world. Many OEMs including VW use Mahle for many of their OE products. For example, in many cases, the filter you buy in a silvert VW box will have Mahle branding on it. Mahle offers the same quality products to the aftermarket that is does to the OEMs. In addition to filtration, Mahle also produces engine parts such as pistons and engine gasket sets. Mahle recently acquired Behr which expands their coverage in to other high quality products such as thermostats and heating and cooling system parts.