I'm not responsible for you frying your wiring or anything of that sort, if this is illegal in your place of residence, do at your own risk.
Well after much searching and finding nothing I tried to tackle the DRL removal. I heard you needed to add a relay, run wires, change relays etc etc. I tried this and fried my fusebox, which actually led me and a buddy to figure out what I hadn't found before.. The proper way to do it, and find out how BMW enables them.
The relays use a switched ground to complete the coil circuit in the relays. If you took a test light, hooked it up to 12v and started poking around the headlight switch you'd find switched grounds. One in particular is used for completing the low beam and highbeam relay circuit. Shown below.
If you follow that wire, it goes through the firewall and ends up in the fusebox connected to nothing, BMW actually put a male connector on the end of it because in non DRL cars it's plugged into the relay terminal 86. But in DRL cars it's sitting in the fusebox covered in heatshrink shown below (I had cut the shrink away at this point)
To remove your fusebox: disconnect your battery and turn the key forward to remove and surface charge.
Remove your fusebox cover
Remove the 3 screws holding the 2 pieces together (1 on the inside by the fender, and 2 inside the box. You may need to remove a relay to get to one of the screws.) Don't remove the allen head bolt, that connects all the power to the fuses and is a pain in the ass to get the nut on the other side back together.
Carefully seperate the 2 pieces and locate the wire.
If you do look at your #86 terminal and follow the red wire, you'll see that it comes off and runs out of the fuse box and is attached to the hood latch with a ring terminal.
What you want to do is take that terminal off, pull the wire back into the fuse box and connect the yellow and green wire, to the red wire that I just mentioned.
To re assemble your fuse box, do the reverse of taking it apart.
If all goes well your headlight switch should work like: position 1, all off. position 2, parking lights and interior lights. Position 3, headlights, parking lights and interior lights.