You could do some homework and look here:
In a nutshell, there are many issues associated with oil decomposing, aka "burning up" at the elevated temperatures of pistons and piston rings. Those temperatures are very much higher than in the sump. Oil rings can and will "cake-up" from carbon deposits originating from decomposing overheated oil, and the oil rings can thus become useless and the engine will gradually start burning vast amounts of oil. Reminds you of some Subaru, Toyota and others?
The common API standards are not strict enough to reliably prevent this. The ACEA standards are more stringent, but in rare occasions also not enough. ILSAC was established to meet those requirements of modern engines from an American point of view.
A good oil for Mirage is compliant to ILSAC GF-4 or the newer and better GF-5. You could also use the new ILSAC 6-A. All of these are much higher in quality than the Mirage ever needs, and also they happen to be in the correct viscosity group.
NB: Recently there came ILSAC-6A and ILSAC-6B. These are different.
Of these two GF6 standards, only GF-6A is a progression and fully backwards compatible with GF-5, suiting or cars well. Then there is GF-6B specifically for SAE 0W-16 viscosity oil and is not meant for the Mirage!
Any brand GF-4 compliant oil will already have more than enough performance headroom for the Mirage so GF-5 or GF-6A is also great but not really necessary.
Because even the very best oil gets exhausted over time, never forget to change it timely before it starts dumping the carbon deposits it cannot contain any more. Carbon deposits on oil rings are there to stay and can ruin an otherwise good engine.