Dante here reminding you 2005-2009 Mustang guys that we still offer Bi Xenon HID Kits for all factory style headlights. So if you guys are looking to at least upgrade your poor headlights to a brighter cleaner light output then this is where you will want to start.
Again this a basic upgrade and it is highly recommend that you adjust your headlight beam after installation to minimize glare to on coming drivers. Failure to do so may result in blinding on coming drivers. As adjusting will not remove all glare we recommend that upgrading to a retrofitted projector headlight or aftermarket headlight.
This kit can take you any where from 15 to an hour to install with basic hand tools.
If anyone has any other questions please do not hesitate to put them in this thread or you may email me at Dante@HIDGuy.Net.
When you smoke tail lights what you are directly doing is killing a lot of the light that shines through the lens. In this case sometimes LED is worse then your halogen bulbs. You can try and go LED but there is no guarantee they will be brighter or shine through your housings better then your halogens.
There is no HID kit that is street legal. So not sure if your asking as you are looking for a kit that is street legal or what. If that is your concern you need to go with a kelvin rating (color) that is OEMish white and you definitely need to adjust your light beam to reflect a certain distance.
Adjusting your beam can significantly reduce glare if properly done. This is the concern as far as legality is concerned.
If this is still a concern then a retro fit or new pair of projector housings is the way to go. In which still not legal but very very rarely if no existent ever seen anyone get cited for it.