Seeing how every week there is an argument discussion about HIDs I thought I'd gather everyone's thoughts up on them.
HIDs are High Intensity Discharge lights. Instead of a filament they work by igniting gas in between two points that have around 1100V running through them. They are extremely bright and 35W is enough, 55W is a bit much really.
First off, are they legal?
No. Not on a MK3 Golf. Not on stock lights, Hella Twins or any aftermarket lights alone. To be legal they need HID approved projectors or reflectors, be auto-leveling (although auto-leveling suspension is fine and also the dipped beam must stay on with the high beam. They also need a headlight washing system.
However, many people run them without problems. Providing the beam pattern is OK, they get through MOTs. However, in stock lights they DO glare. Members on this site claim they have driven past their car with them on and have not been affected by the glare, however. They have also said they have been around traffic cops and VOSA vehicles and been stopped and the car checked and have been fine.
However, as long as you are aware that they are illegal, you run them at your own risk, which, if you are sensible with them, is fairly low TBH.
Kelvin rating. You will see loads of kits on eBay and the like with a XXXXK rating. This is depth of colour. 3000K is yellow, 4300K is crystal white, and what most manufacturers use in their cars as stock, although some use 6000K. 6000K is a very white colour with a hint of blue at some angles, it looks very "modern". 8000K has a fairly blue tinge and is just about the limit if you don't want any attention for them. 10000K and above has quite a colourful tinge to them and kind of defeats the object as it gets duller.
High beams. HIDs are not recommended in high beams as if you flick them to flash someone or want instant high beam in country lanes etc they don't work properly. Saying that, a brand new Audi flashed me with HID high beams the other day (they have high beams HID as stock as a cutoff moves) and it wasn't bright at all and just showed up a dim blue glow in his headlights.
They aren't difficult to install, you need to connect your existing bulb connectors to the ballast that comes in the kit then the ballast to the bulb. It will come with fitting instructions and really isn't hard. You will want to make sure the back of the headlights is sealed though to stop water and dirt getting in.
When you switch them on they explode with brightness then go dim and warm up, this is normal, it takes about 30 seconds to be at full brightness, they are also very blue for the first few seconds.
Shady Pioneer, the moderator of this section, emailed his insurance company and they classed it as a modification with no trouble. This is recommended as it doesn't give them much room in the event of an accident.
If you have Dayglo where the dipped beam comes on dimly with the sidelights, it is recommended you remove it. This is because if you put your sidelights on the HIDs flicker then go out, then when it gets darker and you flick the dipped beam on they don't work. You have to turn it right off then right back on again. Also, mine used to flicker permanently if I had been using them then went back to sidelights.
So in summary, they aren't legal, but as I said, be sensible and the risk is very low. Keep them aligned and it'll go through an MOT. They are very handy in driving at night as as Joe said "you can see further then the front of your bonnet".
