Which Replacement Xenon Bulbs?
 

Torn between:

1) Philips X-treme Vision 4800k D1S

2) Osram Nightbreaker Unlimited 4350k D1S

Any pros/cons for 2005 Cayenne S?

Whichever is cheaper. They're both close enough together in Color that it would probably be hard to tell the difference, and they're both front-line manufacturers.

Yep. Just make sure you get them from a reputable place. Tons of counterfeits on Amazon and eBay. If the price seems too good to be true, it probably is.

That's a good call on counterfeit's, there've been a few posts on multiple forums about that, from Bulbs to Fuel pumps. Chinese copies.

I found some Osram Nightbreakers on ebay with OEM Authenticity code, for $156/shipped a pair. I'll post comparison photos soon!