tons of fine cracks on the inside? common? why?
 

My 2007 has a lot of fine what looks like cracks on the inside of the light housing not the outside. Is this common? I can see from the records this was happening many years ago. Anybody understand why it happened? Can I remove the light fixture and polish the inside of the light fixture?

Keep in mind, once you buff out the headlights you have removed all of the UV protection that there was.....and as the factory UV protection dies it turns that brown/yellow. So....once your buff it out, there is no UV protection left and the light will get worse MUCH more quickly than it did before, and start cracking. The only way to prevent this is re-apply some kind of UV protection (think spraying a UV Clear Coat paint type product on them). Some places, like headlight doctor do this as part of their restoration service.

Good luck.

Can anyone verify if this headlight would match my pre LCI 2007 X5 4.8?

BMW x5 E70 2007 Xenon Headlight with Flasher Right | eBay

That one will fit, looks like is not OEM, it says OEM suppliers

Dealer sells replacement tabs (except the long one) for about $50. Otherwise, I'd recommend going with a professional headlamp lens cleaning service. The stuff they sell in auto stores is a waste of money because it only clears the lenses temporarily.

have you been tried with 3M headlight restoration kit?
I did and it has much more improvement/clear.
the kit is here:
http://www.amazon.com/3M-39008-Headl.../dp/B001AIZ5HY