is it worth buying them?

You mean doing a 5.5gen reflector housing HID retrofit, or just using the bulbs/ballasts? 5th gen's use D2R's for HIDso they won't work on the 4th gen. I thought about retrofitting in the entire 5.5 gen reflector housing setup so I could have separate hi/lows but 5.5 gen headlights are really expensive so it's more economical to just do a projector retro.

If you just want HID's, a bunch of people are selling them on the org: umnitza (prolumen) and maximus_95 (xtec), to name a few.

i was talking about just using the bulbs/ballasts.

so you're saying they won't fit in my headlights?

Not only will it not fit because the base of the bulb is different (D2R vs. 9004), but even if you somehow managed to "make it fit," the beam pattern would also suck.

how about retro fitting the 5.5gen headlights into ours. High and low beam. Will it fit? Or even the CE's projectors for the 5.5? any ideas anyone?

I ran 5g hids for over a year and my advice is to use the ballasts and just buy bulbs that fit your housings that’s what I ended up doing, they 5g hids are good quality pieces so use the ballasts if you can.

I am actually retrofitting the 2k2 HIDs into my old 96 headlights right now as a project. I am sure they will look mean/clean as heck just like on the 2k2. I'll keep you guys updated when I am done.