A few observations on Phil's post because I have been through the same process and swapped most of my bulbs to LED's
UKPhilTR7 wrote: Do not forget that you cannot use the dimmer with led’s though. So what I did was take the dimmer out and just joined the cables together.
I still have the dimmer in place and to my surprise it does actually allow a limited amount of dimming. It doesn't have to be bypassed unless you want.
UKPhilTR7 wrote: Once again if you decide to do the exterior bulbs, you will need to purchase the same colour bulbs as the shade where they are to be used.
Colour is important if you want the white side lights to look the same as the existing yellowish bulbs - use "warm white" LED's. For the indicators, the coloured lenses can be removed and a amber LED's fitted. For the red lights (Brakes/rear lights) use Red LED's.
UKPhilTR7 wrote: I have not changed the indicator lights yet as that will need a new led flasher unit, as the existing one cannot cope with the low led voltage.
If you have fitted an electronic flasher unit, to overcome the common problem of slow indicators due to poor earthing, it will work perfectly well with the LED bulbs HOWEVER you also have to change the hazard flasher (its the same relay as the indicator, but is located in the glove box area) or fit power resistors in parallel with the bulbs - Since I haven't got around to changing the Hazard flasher, for the moment I have 50W 6.8 ohm resistors installed in parallel with each bulb (they cost under 2 quid each)
IMHO the main benefit is that LED lights can be left on for extended periods without draining the battery in emergencies.
Cheers
Howard