I have read through all the HID-related posts on the Lexus GX470 forums and have found that overall, they are very happy with the H11 HID kit from xenondepot. The GX470 should be very similar to our 06 4Runners because both are equipped with Halogen projectors stock and H11 bulbs.
The xenondepot kit comes with a relay and fuse, two ballasts for power to the bulbs (Phillips), the HID bulbs (Phillips), and a wiring harness that plugs directly into the GX470 headlight harness. A few GX470 owners installed the kit themselves in about an hour and were happy with the results.
Now, two things I noticed were...
1. The GX470 owners overwhelmingly ordered the 6000k HID kit. I don't know if that was for looks (more blueish/purple appearance) or what. I have read that the 4300k HID kits are comparable to stock HIDs (such as the Lexus RX330).
2. As I mentioned before, the ballasts and bulbs are Phillips. The GX forums say these are high quality HID parts and are factory-stock on many high-end luxury cars. That, and the fact that the people who have installed the kit are happy with it, makes me more confident in it. I just wish someone could tell me if these Phillips products are as good as the Denso ballasts that come with factory-equipped Lexus HIDs.
By the way, I am not by any means affiliated with xenondepot and have not even purchased from them. I am simply relaying what I read on the Lexus forums. From those forums, xenondepot sounds good, while proxenon and others sound like they are not as user-friendly to install and don't have the best customer service. Just passing this info along to whomever is interested....
I am curious to see the photos and impressions from whoever does this upgrade first in the 2006 4Runner. If anyone has any other info that can help, please add to the post...
Thanks!