Since efficiency of the filter has been broached, I'd like to know the efficiency of the Mopar oem in this filter in particular and the other Mopar cartridges in general. I say this because it very rare that the oem publishes efficiency specs, they are generally kept proprietary. If not for the Amsoil test of some oem spin on filters, those filters like the FL820S would still be thought to be the old vague ~80>20um, the others tested would be a mystery to. So if there is a citing for the standard Mopar cartridge filters' efficiency please post it as I'd be interested in seeing it.
And using the spin on filters as the example, it's not been difficult for the aftermarket filters to have a much better ISO efficiency rating. With that in mind, I personally would be surprised if the Mopar oem is any better than the OP's MG/Wix, in fact if similar to spin on examples the MG may be better.
As for with WixXP, if the spec is accurate imo that is an example in the extreme not the rule. So, while there may be more efficient filters than the OP's MG, I'm thinking it's equal to or even better than the oem, if can you find the spec of the latter.