I STRONGLY Suggest you join Candlepowerforums.com - not for flashlights which are the forum's primary purpose, but to go the the Transportation section, then the "Automotive Motorcycles Included" sub-forum, where you will learn a lot from true industry experts as well as ordinary lighting enthusiasts.
Among other things, you will learn why HID "kits" are not legal, why you should never change the type of light source in a lamp (besides the fact it's against federal law, and you'll learn why that is so), as in halogen to HID or incandescent to LED. You will learn how to do HID headlights correctly, but it's not cheap (the StarrHID headlights in my Crown Vic are low end at $650 sale price, it's easy to spend a couple of grand). You will learn about LED headlight options that are actually legal, as well as why almost all LED signals and tail lights are illegal and dangerous (but there's new stuff coming out as we speak).
Really, you can't put HID into halogen reflectors without altering the beam for the worse. It's more than just focal length. The HID light source is differently shaped than a filament light source.
You may also learn about simple and legal upgrades. My 2007 Corolla came with 9005 high beams and 9006 lows. Now it has 9011 highs and 9012 lows, using halogen HIR technology to put out more light with exactly the same power consumption.
You will learn which auxiliary lights are good an which ones are trash - and the truth is much different than advertising hype might lead you to believe.
Again, I strongly urge all drivers interested in better lighting to join that forum and learn.