ive used white / clear ones and they give a really nice crisp light.

dont be tempted by coloured ones though because theyre very bright and very obvious!

also, a lot of the yellowing effect with sidelights on is actually caused by the dim/dip resistor system which runs a lower voltage through the headlamp bulbs meaning they dont light very brightly. its easy to disable by removing a fuse, and you dont need it by law. once disabled you will only get sidelights when on sidelight, but the proper dipped and main still work as they should.

i dont know any cars other than rovers that use it, certainly none that my family has ever owned. ive used blue coated sidelights before and they are nicer than std ones, but theyre not really noticable unless you compare back to back.

the led ones i used had 4 tiny leds in each, and were pretty bright. i'll be going back to them soon because ive grown out of angel eyes