Chris_D said:
from a practical aspect I'd be too scared to even drive it with those superstretched rears!
I wasn’t too keen about the idea of this either but looked into it over and over and no danger from what I can see and read. It drives soooooo much better now though on these than the 108s with run flats
I saw this too as this guy fitted rears to the front as well and stretched them all
Someone wanting to do the same thing

then someone else sent them this video of someone who’s done it
https://youtu.be/2Or-RXG4FHA