not including BI-xenons. Has anyone converted their high beam to HID? Other than the warmup time, are there any downside to doing it? Distance vision must be great!!! BTW, I have H7 highs.

( printout from: http://faq.auto.light.tripod.com/hl-systems.htm )

Advantages:
1) Can use smaller reflector to achieve same or higher brightness compared to halogen.
2) Lower energy consumption. Physically heavy and amps sucking halogen based light clusters seen on rally cars has become a thing of the past.

Disadvanteges:
1. HID bulbs do not achieve full brightness until the metallic salts in the HID capsule are completely vaporized, which could take up to a minute (or more) on some setups. This means they would not be much good for "flash to pass" signaling or extra light on demand.
2. Decreased bulb life if turning HIDs off and back on again. Continuous use in traffic passing situations would mean many hot re-strikes of HID arc, which shortens HID capsule life and requires MORE startup current than a cold capsule, thereby putting added wear & tear on your wiring and switching components.
3. Higher price. HID based systems costs more.

None of the above is a problem with a OEM "bi-xenon" setup, since the high/low is accomplished thru a mechanical moving shield and/or moving reflector, and the actual HID capsule remains constantly on, with no warm-up or hot re-strike required.

I got HIDs (complete HID designed fixtures) for highbeams on my truck. I had also tried just HID capsules in my car for awhile in my 9005 highbeam sockets for about 2 months. I took them back out on my car and currently use 9005 halogens because they were plenty bright before, and I needed the kit more for something else. But I left them on my truck, since they were H4 and my highbeams are driving lights designed for HID bulb. The output is really impressive on my truck. I have them aimed to see right above cutoff, and they extend really far. They are these ones:

I DO like the output of them, but they do NOT get very bright (to a usable point) for at least 5 seconds. But I always plan around that while I'm driving (my justification). Also, to help extend bulb life I always allow at least 30 seconds of cooldown time before re-striking them each time too, so that the capsule isn't still glowing bright cherry red as I hot-restrike. And they've lasted 2 years just fine like that All in all, I like them, but if you got decent highbeams now, then I wouldn't bother. Like I said, since my car produced bright highbeam with 9005, I did not want to sacrifice the instant-on thing if I didn't have to.
The only other option I've considered is to try an HIR retrofit (Halogen InfraRed technology). Those bulb types use an IR reflective coating on the inside of the glass capsule to reflect back the wasted IR (heat) rays right back towards the filament, and it in turn makes the filament glow much brighter. They are said to approach the levels of HID lightsource. Actually, I think they are around 2600lm or something (I really don't remember exactly). The Dodge Vipers and I think Toyota Camrys use them for OEM I think, so I might try putting some in one of these days to see if they would provide a significant increase in lumen output.