I have a set of those in my garage!
I don't think you NEED the euro manifolds, the US ones will physically bolt up, I am 90% the exhaust ports are the same size. The only thing is is that you'll put a cork in the motor so no more 300hp... So I guess you could say it is highly recommended you get a set of euro manifolds!! Or...get a set of these made...
Scroll down a little over half way.
'86 420SE Euro
904 Midnight Blue, Gray Velour
Dad bought it new, now I own it.
"A Mercedes-Benz is like a fine wine, it only gets better with age."