I received my LED Headlamp Kit and the W5W lights from XenonXtutti and fitted them on Sunday (well the headlamps anyway). As you will see from Rollerleg's pictures they come with two black boxes - the first is for LED drivers I believe and the 2nd for the Canbus? I tried with just the first box and they work perfectly so a significant reduction in cabling and black boxes. I have tried to fit the W5W bulbs but my hands are just too big to reach them so I am waiting for my daughter to pop around. She has very small hands and is a capable mechanic too! The headlights work really well with good cut off but the front still looks so weird with a mixture of nice white lights and a bit of yellow thrown in there! Remember don't order the (alleged) Osram H19 LEDs from FranceXenon as they are just standard H4s and the beam pattern is just rubbish. Even though I recovered my money via PayPal the French outfit still advertise them as being H19s and claim they are exactly the same as H19s!!!
Glad to hear you have the lights mounted. The two black boxes on it are:
1) Canbus adapter (required).
2) Ballast (recommended).
The ballast is responsible for adjusting voltages and providing the exact current to the led bulbs to optimize their operation. They can work without the ballast, but normally you will shorten the life of the bulbs.
Personally I recommend you to use it, but I am not able to tell you how much percent of the bulbs life you will lose.
In my case it is already mounted with both and I don't plan to dismount it again hehehe.