I would recommend
http://www.ddmtuning.com - that's where I got mine. The prices were VERY reasonable. The ONLY issue I had with them is that they had a hard time getting the 6000K H4's with the Hi/Low like I wanted so it took about 3-4 weeks longer to get them than what I had anticipated...but once they arrive and got installed...AMAZING!!
Also, check out my thread I made about them for a few pics...
zerothread?id=414865
Of course, if you want a blue tint then you'll need to get a higher color temp than the 6000K. Also, the DDM kits come with the ultra-slim ballasts at NO additional costs unlike some other websites! Give them a shot, check 'em out!