To answer the two above questions.
1) Royal Purple has shown less than stellar UOA results. Additionally it is a Group III oil, which makes it very high priced for what you get. Do a search and you will find the answer.
2) Delo 400- Your right, check the FAQ. In short, 40 weight oils are ideal for the LC engine. Delo as a fleet vehicle oil has a roboust additive package and a high grade Group II+ mineral oil stock. Wear numbers have been consistantly very good with that oil. Also, many European manufactures recommended these Fleet oils as their recommended oil for years because of their superior durablity compared to most mineral oils. That said, any name brand SL or SM oil in the appropriate weight (5w-30, 10w-30, 10w-40, 15w-40) will provide more than adequate protection for a stock 80 engine in 99.99% of situations.
1) Royal Purple has shown less than stellar UOA results. Additionally it is a Group III oil, which makes it very high priced for what you get. Do a search and you will find the answer.
2) Delo 400- Your right, check the FAQ. In short, 40 weight oils are ideal for the LC engine. Delo as a fleet vehicle oil has a roboust additive package and a high grade Group II+ mineral oil stock. Wear numbers have been consistantly very good with that oil. Also, many European manufactures recommended these Fleet oils as their recommended oil for years because of their superior durablity compared to most mineral oils. That said, any name brand SL or SM oil in the appropriate weight (5w-30, 10w-30, 10w-40, 15w-40) will provide more than adequate protection for a stock 80 engine in 99.99% of situations.

FWIW