I would look to buy a full set of winter tyres and wheels.
17" are more common so cheaper. I bought a full set of 19" wheels with nearly new tyres from an ex CX-5 sport owner, he had numerous issues with his car including excessive oil rise.
So he traded in for a Kuga.
His cx-5 had his winter wheels on which were the 17" wheels on trade in, so he sold the 4 spare OE ones to me, for £650 which i thought a fair price considering the tyres are around £135 and wheels at the time £210 each.
I've seen wheel sets for resonable money on the "on line" tyre sites. look under winter wheel sets or simular. You only need to store three and carry the other as a spare.
He did say the handling wasn't as good on the 17" wheels in his opinion.