You're in luck - eur1409 fit 550i, and should 650igc 650i etc.
I got at rockauto.com for 80+36 shipping .. really good, didn't have to even bother with asking tirerack for a quote and wire if they don't take credit card
They have eur1409 too:
But you have confirm this, i just know know EUR1504 is fitted snug and well on my non-high speed brake 528i.
Also this is useful to check your VIN .. turn out I been looking at realoem wrong all this time, the HK 528i is actually a 530i according to the official VIN
You can find the VIN on every body panel and windshield, but I was dumb and opened the front to find it under the hood