Need some advice. BMW guru Mike Miller uses Red Line 75w-90 in his vehicles, but I've read that the fluid doesn't last nearly as long as the BMW fill, which I understand is Castrol SAF-XO. Land Rover sells the SAF-XO oil as part # LRN7591 for $25 a quart at the dealership nearby or I can order it for $20 a quart online. With shipping, it's a wash on prices. What say ye, Red Line or LRN7591?
'99 Volvo S70 - QS 5w-40
'01 F250 5.4L - MC 5w-30
'02 Kaw ATV 650 - M1 TDT 5w-40
'06 Scag Fr. Z - M1 5w-40, 15w-50 tran.