I have mixed/used 100 octane aviation fuel (NOT Jet fuel) in vehicles and it's fine for high performance, costly tho. However I would NOT mix/use Mobil Jet oil in a car. Here is an explanation of applications and usage:

Applications

Mobil Jet Oil 254 is recommended for aircraft gas turbine engines of the turbo-jet, turbo-fan, turbo-prop, and turbo-shaft (helicopter) types used in commercial and military service. It is also suitable for aircraft-type gas turbine engines used in industrial or marine applications.Mobil Jet Oil 254 is approved against the High Thermal Stability (HTS) classification of U.S. Military Specification MIL-PRF-23699. It is also compatible with other synthetic gas turbine lubricants meeting MIL-PRF-23699. However, mixing with other products is not recommended because the blend would result in some loss of the superior performance characteristics of Mobil Jet Oil 254.Mobil Jet Oil 254 is completely compatible with all metals used in gas turbine construction, as well as with F Rubber (Viton A), H Rubber (Buna N), and other commonly used seal materials.
(All of the builder approvals are aircraft engine builders) Clearly this product is for aviation use only (Turbine engines)