Which ever route you go, please post pics. These are not my priority mods until I see ones that come close the the newer 3 series and X3 version as they are extremely well lit in white. I've seen some after market ones on the street and I think my stock yellow looks brighter.
The brightest I've seen are Persian54's, but I believe they were custom fitted for his Z4.
2010 BMW Z4-35i AW/Red, 6-spd MT, Dinan: Stage 3, Flywheel, & FMIC, Eisenmann Race Exhaust, KW v3, H&R Sway Bars, ACS Type 8 Forged Wheels w/ Michelin PSS, Alpine HID.