I've used these before on my Vdub 10 years ago and were great. I actually used the X's horn a few days ago and was not impressed, I could barely hear it, let alone someone outside.

My only question: Are you sure factory wiring is OK? When I tried it way back then with factory wiring in VW = not enough juice to power the air compressor. I always ran dedicated copper to the battery.

I have never installed Hellas in all my other BuMW sedans since the engine/nose was so tightly packed. But the X5 has loads of room.