Replaced run flats and looking for spare option

[RouseandFable]

So i finally made the leap and replaced my run flats. Only had them for a year and had one blow out in the first few months and recently noticed one of the tires was starting to bulge on the sides. When the dealer said i should replace 3 out of the 4 i decided to replace them altogether with non run flats as they have been more of a headache then their worth. The only thing i regret is not doing it sooner. Difference is night and day. I went with the Micheline Pilot Sport 4s which grip like there's no tomorrow and offer a much smoother ride in general. The car even feels lighter.

What i'm wondering about now is what my options might be for a spare. I have a 2016 328i Touring with the M Sport package including the M Sport brakes so not sure if any basic spare tire would fit.

[MIKYZZ4]

Ideally I would have chosen the 1 out of 4 the dealership chose not to replace as a RFT spare,
mounted to correct spec rim/wheel obtained from a salvage yard,
as you have a touring with no cramped space limitations.