[Msquared]

Not a ZLE, but I just began running Supercar 5w-50 as my all-purpose oil in my SS 1LE. I made this change when the car stopped being my daily driver. I use it for autocross and track days, and it still gets driven to/from events and the occasional other duties as assigned.

FS X2 and Supercar 5w-50 are definitely not the same oils, so you can't apply the specs from one to the other. And Mobil frustratingly doesn't publish an HTHS number for the Supercar variety. However, Supercar actually has a slightly higher 100C viscosity and a fair amount of zinc, so my guess is that its HTHS is slightly higher than that for the FS X2 (which Mobil specs as 4.3).

I don't know enough about the Motul products to say if you need to switch, but my guess is that it would still be a good idea.