My 217 80th anniversary Plus 4 which I bought in 2021 had been fitted with SSL suspension by the previous owner.When looking for a car I drove five others all of which had unmodified suspension before buying mine. It seemed to me that the handling on the SSL one was so much better than the others I tried. I have been told that there may be an issue of reduced rear suspension travel but I have not experienced it in the three years I have had the car.
