There is a similar situation when converting a car from halogen to xenon units. The Department for Transport takes the view that the sale and use of aftermarket HID lighting kits is illegal, but due to the European regulations mentioned above, makes expectations. While anyone looking to convert to xenons should carry out rigorous research, the key points to consider are:

· • The headlamp must be type approved by the supplier

· • The headlamp must have self cleaning and self-levelling capabilities

· • And finally, it must be maintained properly (as with any other headlamp) 

Xenon lights pros and cons 

Pros

• Lifespan. Xenon bulbs can last up to 10 years, making for good piece of mind.
• Brightness. As high intensity discharge would suggest, xenon lights are brighter than there halogen counterparts

Cons

• Cost. if you are buying a used car which has xenon lights and is coming up on 10 years old, good replacement units aren’t nearly as cheap as you would hope.