They can work on a stock w124 - i am running 8 x 17 et 30s on my w124 300te estate, agressively lowered with Spax springs/shocks, no rolling of arches and i have no issue...although you have to run the tyres a bit skinny. Rather than 225/50 run 215/50 or even drop the aspeect ratio to 45, that will help. Ensure the rolling diameter is not compromised more than 3% of course.
The stock 500E wheels were way to high an offset...the car can take 8 inch wheels with a negative offset thanks to it's wide wide arches !
I love the wheels, merely due to their association with 500E's !