Aftermarket HID Kit?

[willy_manily]

So my 2006 E53 didn't come with factory xenon lights (massive PITA). However the car does have standard projector lenses. I want to know how easy it is to install an aftermarket HID kit.

On my old car I just purchased a HID kit from eBay and installed it with pretty good results. All I had to do was still a small hole in the rear of the headlight to run the cables out of. Is it the same for the e53? I've heard rumours of the bulb holder being different so it needs to be modified to hold the hid bulb. Is this correct?

Also, what colour/wattage would be suitable? I'm leaning towards a 55w H7 kit in 6000k.

Now I know people are going to suggest that I look for an OEM kit. In Australia they are hard as hell to find and cost a small fortune so as far as I'm concerned it's out of the question.

Anybody with any experience in this?