alex a6 allroad 2004

great advise this above, mine is on 204k just got it 3 months ago. runs great but don't no what oil I need to buy. well I do now. what I didn't no is what type of sieving I should go on. short life and inspection or longlife. the car will do 8k a year from now on but will be towing 1 to 3.5 ton every mile it does. it wont be driving unless its towing. any advice. this is a towing work horse car only and I want to look after it.