I'm looking to install a Eaton/Detroit TrueTrace Torsen differential in the near future. The owners manual states: --- Detroit Truetrac® High quality mineral gear lubes are required for use in Detroit Truetrac differentials. Regardless of the lube type, always use a GL5 rated lube with the least amount of friction modifier. Mineral lubes lacking friction modifiers (limited-slip additives) were historically recommended for all Truetrac applications because friction modifiers can slightly reduce the bias ratio (limited-slip aggressiveness) of Truetrac differentials. However, to address the continually increasing power outputs of modern powertrains, many vehicle manufacturers have switched to synthetic lubricants as a counter measure for increased axle temperatures and prolonged service intervals. In general, consult the vehicle owner's manual for the manufacturer's recommendations for lubrication type, weight and fill volume. This will ensure lube compatibility with the seal materials and bearings used in the axle. Eaton Performance technical support is available for any concerns in lube selection. --- The factory fill recommendation for the OEM rear-end is a synthetic 75W90, but the factory differential was not a Torsen design. I'll be using either the OEM axles, or aftermarket replacement axles. Some are saying "140 is too heavy for a Torsen. No manufacturer will recommend an oil that heavy, it will change the friction levels the diff relies upon to function to its fullest", while others are saying the 140 will reduce noise. Application will be daily driver that sees some autocross and HPDE sessions (20 minute sessions of limited passing). I've found the following gear oils without friction modifiers, should I consider any of these or look elsewhere?