Just a bit of info based on working in Mfg and supplying parts & sevcies to the machine tool and automotive industry.
TRW is well known for automotive parts. It is a very good brand. I believe Dack is correct but to be more precise. TRW probably has two specs; 1) for BMW 2) for OEM, so the OEM parts are not necessarily out of spec. The specs are just tighter for the major client (BMW) which costs more to produce and less stringent for the other clients in order to lower the price. We do the same with our Mfg in order to serve two segments of the market. High quality and price conscious. GL
Just my $0.02.