From M-1's website: Mobil 1 with SuperSynTM 0W-40: Flows at -54°C (-65°F). Meets ACEA A3/B3/B4-02 and the performance specifications of European automakers, including Mercedes-Benz, Porsche and BMW. Approved against both MB 229.3 and MB 229.5 for use all Mercedes-Benz passenger vehicles. Specified on the Porsche Approval List 2002 and is factory fill for all Porsche vehicles. Approved against BMW Longlife 01. Approved against Volkswagen/Audi 502.00/505.00/503.01. Approved against GM (Saab/Opel) GM-LL-A-025 (gasoline) and GM-LL-B-025 (diesel). Mobil 1 with SuperSynTM 15W-50 Flows at -45°C (-49°F), pumps at temperatures as low as many conventional SAE 5W-30 oils. Provides superior high-temperature protection for high-performance and high-revving cars. Contains additional wear protection required for racing type engines. The 0-40 has a plethera of qualifying specs...can the same specs/qualifications be extrapolated to the 15-50 or is the 0-40 simply a better oil?