I have replaced my 103's (possibly up for sale shortly if anyone's interested
) with the standard M wheels- I owe thanks to TOM14S and JackB1 who posted very helpful write-ups and pics on their experiences of this move!
While I'm in Oscar speech mode, a massive thanks to David (dgm) who proved there are trustworthy people left on Earth after not running away with my money and sending me wheels he had expended LOTS of time and effort to prepare and package- much appreciated!
Before:

After:


For anyone thinking of putting M wheels on their non-M Zed and concerned on the fit, here's how the rear looks under the arch:

The ride is improved over the Runflats even though the tyres are lower profile (I think) and wheels are bigger, and I am yet to feel any rubbing- very VERY happy with them
While I'm in Oscar speech mode, a massive thanks to David (dgm) who proved there are trustworthy people left on Earth after not running away with my money and sending me wheels he had expended LOTS of time and effort to prepare and package- much appreciated!
Before:

After:


For anyone thinking of putting M wheels on their non-M Zed and concerned on the fit, here's how the rear looks under the arch:

The ride is improved over the Runflats even though the tyres are lower profile (I think) and wheels are bigger, and I am yet to feel any rubbing- very VERY happy with them