Problem with HIR's are the availability, and also that you need to do a very slight hack to their base to retrofit them to 9005/9006 sockets. No big deal.
HID's are great too, as long as you get them in a reasonable color temperature, and DO NOT use them in the factory housings on the 88-98 trucks! The lack of a "glare cap" allows for so much glare all you end up doing is blinding everyone else on the road. This is where housings like the TYC Elegantes I mentioned before come in handy. They have a cap over the end of the capsule, similar to the late model trucks, which really cuts down the glare. I've got 5300K HID's and the TYC housings on my '94 extended cab. Light is almost white, near factory color, not any of that annoying blue ricer effect.
(Edit - there are also HID capsules that are designed for reflector housings, instead of projectors, which have their own covering on the end of the capsule and a sleeve around the light-producing portion that controls the output of the light. They're not the easiest thing to find though and you also won't find them in the inexpensive aftermarket HID conversion kits. The reflector style HID capsules are an OEM Phillips item and are a couple hundred bucks just for the capsules, then you still have to buy ballasts and connectors.)
Richard
