I didn't get the HID option, but now I'm wondering if I can retrofit the factory HIDs.
has anyone done so?
Are they expensive---is fitting them "plug & play" or complicated?
It would probably be a lot cheaper to get an aftermarket kit than to try to swap out the standard headlights with the factory HIDS. The headlight assemblies from ford are compeletely different (blinker on other side of light, etc) but an aftermarket kit can reuse the same housing as the Ford non-HID headlights.
Don't do it. Your stock reflectors are not set up for HIDs. If you do install aftermarket HIDs, you'll be one of those clowns on the road whose headlights blind everyone.
If you want HIDs, do it right and get the OEM HID reflectors.
Well all you really need is the two OEM headlight housings and the wiring harness (since the turn signals are different). You could probably get an aftermarket HID kit to work with that if you don't mind splicing some wires.
I was looking it up before I ordered my mustang. It seems like its a tough job and will cost you quite a bit. You can go on ebay and find the OEM light housing for a couple hundred, then you can use a hid kit with it and have your HIDs done right
-Two Factory HID housings
-New harness for the headlights (not due to turn signal but rather the ballasts that fire the HID bulbs; the distance between the turn signal seems inconsequential)
-Two Factory spec HID bulbs for the housing
You should be able to ground the ballasts in the stock manner, mount them in the same manner, etc.
The biggest part seems to be replacing the non-HID wiring...
I would suggest going to a local Ford dealer that has an HID equipped Mustang and checking under the hood for mounting locations etc.
I had HID installed for $250. They are available from Extreme Lighting Accessories. They are 6300k Ultra power light in white and not the blinding 10000k blue lights. They connect easily to the factory harness.