Pirelli P Zeros
 

Looking at these for my 20" setup, worth the money? I dont see a lot of options listed for our wheel size...

Is there a Bmw air kit that can be purchased in case of a flat?

The BMW M Mobility Kit is exactly what you're looking for. The kit contains a leak sealant, small air compressor, and black work gloves. Use it to reseal a tread puncture, re-inflate the tire, and drive to a service facility for a proper puncture repair. I have the kit available HERE.

http://c1552172.r72.cf0.rackcdn.com/207938_x600.jpg

I had one of these in both my X and wife's car along with a spare 16oz of Slime just in case.

SLIME – Worldwide Leader in Tire Care – Repairing a flat tire? Slime Tire & Tube Sealant » Catalog » Catalog Products » Smart Spair Flat Tire Repair Kit (SS-PDQ/06)