This is the first truly useful lighting modification I have seen on this site. I think the mods on my car will be limited to your DIY and a set of Euro taillights (I don't like the look of the blacklines).
2008 BMW 535i Space Gray, Black Leather, Dark Bamboo Trim| Sport Automatic with Paddles | Sport Package
2008 BMW M5 (gone, but not forgotten) Space Gray, Silverstone Merino Leather, Madeira Walnut Wood Trim | 7speed SMG | All options
Mods: Corsa Exhaust | RPI Ram Air Intake | H&R Sport Springs | Rogue Engineering 12mm spacers