You can actually get a 4300k globe in other brands, that does have a slightly blue-ish tint on the globes, that is designed too replicate that blue-white light effect, that you see with Diamond Vision (or with HID globes if you're that lucky too have used them), but they won't have anywhere near the penetration/seeing distance that the Xtreme Vision globes have.
Even though the Xtreme Vision are only 4300k globe, they do say as a stated fact, that 4300k globes are as close too natural daylight as you will get, so yeah they are still a little yellow, but they're definitely closer too white, than a stock factory globe.
The guy from Inivision (who are the importers of Philips automotive globes in Australia, that I mentioned earlier), did say that because the Diamond Vision globes are 5000k, that they have a seemingly thicker coating on the globe, in order too get that blue-white look, which in his opinion, is why they don't penetrate anywhere near as well as a 4300k globe, and they burn out quicker.
Besides the fact that they're not ADR compliant, that was his opinion, and they deal with Philips on a daily basis, so I'd put his opinion at a premium, simply because he knows the Philips range like no-one else.
If it helps, I was hell bent on getting Diamond Vision, because I liked the look, and I was sure that seeing distance would be better, because of the light seeming too be clearer, but after speaking too him, I became a firm believer that there was only one way too go, and that was Xtreme Vision.
Anyways I hope it helps mate