Any aftermarket kit that replaces H7 bulbs will work. There are many different ones available. I'd suggest you stick with one that uses name brand components such as Phillips, Hella, etc. It's also preferable to have a single ballast unit rather than a separate ballast and ignitor for each bulb, installation is easier and there is one less component to fail.
As for color it depends on the particular kit and what bulbs are being used. Check the color temperature rating- 4300-4500K will provide the whitest light and the most usable illumination, as the numbers go up the light becomes more bluish and by 8000K it's noticeably purple.
Considering how much you will be spending on this it's best to actually see them in operation on another car first.
I have 4300K HIDs in my Morettes with Phillips ballasts and they work well and produce white light.