Don't buy those cheap bulbs,
1) trying to be an HID poser isn't cool, you wanna know how many mid 90's beat up vehicles driven by kids under 25, I see with fake blue lights?
2) they don't last long, I will admit, I tried them myself a few years back, and I couldn't keep a bulb for the life of me. I put the original stockers back in, that I had saved (just in case) and never had a problem.
3) I've read lots of articles on these "cool blues" and from most of my reading, I've learned that, unless they are true HID's, the blue coated bulb, actually puts out less light. It seems brighter, but when on displayed onto the road, our eyes see yellow better for some reason (something along those lines)
Bottom line, don't waste your time, unless you got the $$$ for HID's