After five years of ownership with our Mini Cooper S (F56) today we've finally ditched the run flat tyres in exchange for some Michelin Pilot Sport 4 rubber. ... Should've done it the day we bought the car.
Couldn't agree more. As soon as the runflats that came with the car were worn I replaced with them normal tyres. No more timing or dodging cat's eyes on the motorway when changing lanes. Since you don't have a spare I'd recommend a tyre plug kit and a can of tyre weld - not so useful for sidewall punctures though.
Nice, what are these going on? I've got a set of X10s on my i3.
Well recognised! The X10s are now on my 640D along with the Michelin CC2s, I'd love to see them on your i3

. The change from 20" (275/30 & 245/35) to 18" (245/45 all round) doesn't look too drastic, see for yourself below. I think it obviously looks better on the 20" and the 18"s are only for the winter months.
Before with 20" M Sport wheels:
Now with the 18" X10 wheels: Should have taken the picture at the same angle, sorry!
The new wheels are very similar to the originals, somewhat on purpose. I need to get some BMW centre caps to finish it off as my originals are not in great shape.
Regarding the Michelin Cross Climate 2s, I've only driven about 80 miles in them so far so it's a bit early to be making judgements. However, I have noticed the car requiring a lot more micro adjustments to the steering as before, on the exact same roads. I don't know if this is attributable to the smaller wheels and tyres, the tyres being fresh out the poke or the all-season tyre type. I'll be checking the pressures and re-torqueing the wheel bolts since the wheels are new. It's also booked in for an alignment check because the old outside rear tyre had some strange wear on it's inside edge.
All in all I'm happy that I won't get stuck should it snow this winter.