HID's are illegal unless the vehicle comes with them as standard for example D1S, D1R, D2S, D2R etc. HID's which have been made to fit standard bulb fitments are illegal such as H1, H4 (Micra and most fitting cars), H7 etc. Though people still fit them and get away with it.
But if he wants something more along the lines of styling without breaking the bank, You can get Xtreme Blue +50% legal bulbs, which give off a nice blue reflection in the headlamp and is 50% brighter than a standard bulb. If you look at my blog I have put Yellow +30% in my headlamps and they have a nice reflection though I will be putting Xtreme Blue in later as I was only experimenting.