After fitting, I completely agree. The reported problems in the US must have been using loooooong bump stops from the non-sport setup, with very aggressively lowered springs. As you say, the MSport bump stops would have been absolutely fine with Eibach springs.
And again, considering the B4S are supposed to be OEM replacements for the sport setup, there is no way they'd fit with the MSport springs, the springs would have to be compressed like crazy to even get them on the damper. Very odd.
Just how many Yorkshire sheep can you fit inside one exhaust?