Fitted a pair of led lights as DLR's to both mu Z3 and my Z4, the cars low stance always struck me as being easy to miss seeing by other road users. On the Z3 I fitted them to the fog light blanking plates as I dont have fog lights, wired up to a drl relay in the engine compartment left hand side and powered from an ignition controlled circuit in the fuse box using a piggyback fuese tap on an exhisting circuit.
Same method of fitting to the Z4 but these were fittited to the lower plastic mesh grill at either end. The leds used were these
The wiring on these is ultra thin and a bit of a faff to connect to an extension, used solder and heatshrink to joint mine.
If you use a drl relay that requires one of its cables tapped into a sidelight +cable that will deactivate the drl's when sidelights/headlights are in use. These relays also available on ebay
Since fitting these I have only had 1 fail due to water ingress, simple enough job to put a replacement in as the original purchase was for ten of these lights, the others have not had any problems with water ingress so far.