You should use 4.5 liters of motor oil for S2 service. Choose a normal producer of Mineral 10w40 oil to fill up S2 2.2 engine. It has model code ABY and is prepared to work with Mineral 10w40 type of oil. In 1995 the company Audi used to install 2.2 engine in its cars. Better oil Audi S2 engine with needed quality.
With good technical work your Audi with 2.2 motor will be really everlasting. In all situations 1995 Audi S2 should get exact and quality service. It’s only 4.5 liters of Mineral 10w40 oil and your car is safe for 7500 miles.