Ticalis is right about not able to change the colour of your HID.. but wrong about the bulbs being visible at night behind HID. As the bulbs are located side ways on the IS housing, it is not visible from the front , unless u kneel down to look. But these bulbs are clearly seen side on if a cop pulls next to you.. that's how i got fined for having these blue bulbs. Motorcycle cop pulls right besides me and looks at my lights for no damn obvious reason! The PIAA PLasma Bulbs (Very white purple tint lights) did nothing to hide it...
Check the INSIDE AND OUT FORUM for pics..
or visit my site at www.geocities.com/trd328
go to gallery section and it links to my photopoint a/c. There are comparison pics between blue bulbs and hyper white bulbs for parking lights/DRL.