thanks Wenier, They got back to me what I was struggling with was that they say that the 10-40 is suitable for a 10-30 oil recommendation and same with the 15-50 is okay if a 15-40 is specified, was concerned it might be a bit thin if the 10w-40 is okay for a 10-30, but they said its fine. What do you guys rekons best to run out of the 2?