I'm sure others who have actually tried many types and sizes of wheels on their E500E's will chime in, but as a novice to the E500E arena, I would reject the wheels based upon the sizes being outside of comfortable limits. I have several sets of wheels meant to be swapped between my 500e's or SL500's. I only purchased wheels that are known to work on a E550E or a R129, they are basically interchangeable between the two cars.
I would target wheels that are max 8" front & 10" rear, with ET's in the upper teens to low-mid 30's.
I reject ever having to use spacers to make a wheel fit, but others don't care.
My opinion as a beginner at 500E's; the front wheels "May" be too wide, and certainly the ET will need major correction - 20mm spacers up front, 10 mm for the rears, very long custom lug bolts, (you'll need different length lug bolts for the fronts and rears, 10 ea 20mm longer than normal for the fronts, and 10 ea 10mm longer than normal for the rears). I couldn't live with that, potential for rubbing, spacers, oddball lug bolts, handling concerns.
But then again you see all the low riders, and cars with too-wide rims, someone always makes it work and disregards the normal concerns. A personal thing, some care for looks more than performance.
Good luck finding what you want. What wheels are you looking at anyway?