Do you know the center bore? Might you be able to measure it for the forum?
5x4.5 = 5x114.3 I agree the difference is small. I've often questioned whether you could make wheels of this PCD fit will. I hadn't realized Wobble Bolts exist until a few months ago. Here's a link to a picture of how wobble bolts work: VWVortex.com - how do wobble bolts work
I'd definitely want to make sure the concentric rings are perfect. That's why I ask for the center bore is. That would allow the buyer to make sure they can get the rings and wobble bolts that are required to make these fit a Benz.
I don't know about a w126, but the tires are too big to fit on the front of an r/c107. I imagine it is possible that the 225/60/16 tires might have too much sidewall bulge to fit on the back of an r107 without rolling the fenders too. with 225/50/16 on 8x16et11 wheels, I measure an average of only about 14mm before my tires would get cut by the fenders. From what I understand, the taller the sidewall the wider the bulge. I think that's hard to measure without trying it out.
The outside front corners of my 225/50/16 tires will rub the back of the air dam when turning (always while turning and braking in reverse). So I know that the larger diameter (with the same wide-stanced offset) will be a problem on the front of an r107.
I bet they'd fit a Chevelle pretty well with no problems though.