Retrosolutions

Two very important points need to be made here:

1) Most 2006, and all 2007+ Mustangs should not install HID kits into their lamps without purchasing from Retro-Solutions with the bulb capping service. Otherwise there is nothing in those lamps to block directly emitted light through the bulb tops. They simply will blind other drivers like pointing a flashlight in someone's face at night, and no other manufacturer, vendor, or reseller is offering any coating or capping service as Retro-Solutions does.

2) There are only two companies in the US to provide real 55w (and/or 50w) HID kits in the US. One is Retro-Solutions, the other is exclusive to Ebay. All other companies advertising 50w/55w kits are offering 50w ballasts and overpowered 35w bulbs in a kit. This mismatching of generic equipment has its drawbacks, as indicated below.

35w bulb with 50w/55w ballast (most brands):
1) higher temperature output, may damage housings
2) higher arc position, equates to more glare
3) lower color temperature, K color decreases or "color wash-out"
4) reduced lifespan of the bulbs
5) reduced output, inefficiency leads to less than advertised output
6) internal pressure closer to maximum (~60-75w peak), explosion hazard

55w bulbs and 55w ballasts (like DIGITAL 55w brand from Retro-Solutions):
1) lower temperature, safe for housings, produces less than 55w halogen bulb
2) spaced cathodes, same arc position, no increase in glare
3) color correct specification, you order 5000k you get 5000k
4) bulb lifespan maintained
5) efficiency maintained, better efficiency in terms of output
6) internal peak pressure rating of bulbs is greater

Please be very careful in making your decisions, because vendors typically misrepresent their product or withold important information on purpose.

Goldenpony

I have 35W, 6K BiXenon kit from RetroSolutions. Very high quality kit with lifetime warranty.
I love them.