Spring has arrived and time to replace the oil. Have been using Mobil 1 15w50 for my summer oil but no one has it around here. Spoke to my local wrench and he has Motul, I believe he said 20w60. What you all think. Also can get AMSOIL from not too far away. What do you all think of AMSOIL? ?What grade, 5w40? I'm leaning towards MOTUL. TIA Tony 96 S6