+1What is your budget? if you want to have the best setup...Euro headlights made by hella with AIB V3 and D2S 6000k bulb and stealth bulb turn signal is your goal...but you can start with the Euro headlights first,you will also need a upgraded mounting bracket for 2001 and up (this is about $30-40 each from the dealer) and hella upgraded plugs $69.00 for both so you don't have to cut wires...
In terms of overall for M5s, it's a great value:Umnitza has the same kit for $869. I've had nothing but good experiences with them throughout my lighting upgrades (new headlights and xenon fogs).
I got the Projector39s, as opposed to the Hellas, though. I couldnt be happier (and I got them with a 50w ballast, so they really light up the night).
HELLA:I have a 2000 M5 (12/99 build) and want to upgrade also. What's the difference between the two kits?
MY00 cars have a 3 wire connector to the turn signals. It's a bit more expensive and cumbersome to install the MY01-03 headlights on it. We've done it many times and it's just more of a pain to install them.
As for practical differences:
1) P39s have brighter angel eyes, similar looks to OE, and simple bolt on installability.
2) Hella have OE/Germany construction, quality optics, and great fit and finish.
there are positives to both.
you can change the angel eyes to whatever you want
You'll need extra hardware to make it work on your car (pre 2001)
Cheaper than OEM
I wasnt able to tell a difference in qualiy
You can't change the angel eyes. They come with white predator ICE, and that's it.
No need for extra hardware, but you gotta tap power from the parking lights for the angel eyes.
You will lose the auto-leveling feature unless you specifically ask for it, and I think that regardless of the kit (hella or p39), you'll need to get new ballasts since the new ones are H7 and our stock one was D2S (don't quote me on that last one, I'm not 100% sure of it. Maybe someone can confirm?)