Even though not merried yet,
I would let her take X as long as she feels happier driving it, and I'm not stuck with piece of shit car
Anyway I would try to tell her to try and mentain it as I like it.
As for snow tires, in that situation I wouldn't put it at all. Put it on Land Cruiser, That is one car that No metter how you abuse it, Nothing will ever happen to it, IMO.