[W126 Coupe] functional spoiler?

[Shayegan, Richard]

I saw item number 7962466733 on ebay. I'd probably never do it. I think
even a lip spoiler would look pretty bad on a W126, probably ok on an
SEC but definitely not on the sedans. But either way, is there any way
that it actually provides a functional amount of downforce like he says?
My dads 5er feels much more stable at speed, especially at speeds higher
than 100, than a W126 I find. Of course, if this does work it would add
to drag so there probably is some trade off involved.
Richard