RAFBMW1

Hello Guys, First post and after some advice, So I just bought a 60 Plate BMW 1 series M sport coupe. I was driving yesterday and a BMW when past with the hid lights like a blue/purple color it was the same car as mine just a 59 plate and it looked very nice. I was wondering if it would be a HID kit or something else, if i was to buy a kit would I need a certain brand and new head lights to support the new bulbs also would this affect my warranty with Williams BMW. Also the back of my car says 118D but log book says 2.0D i was always under the impression the the BMW number on the back the 118 would refer to the 1 being the series and the 18 being the engine size and this would mean the car is a 1.8 l is this correct or is my log book wrong and the car is in fact not 2.0l but a 1.8l Thanks for looking guys and thanks for help if you reply cheers.