I have read several threads related but couldn't find anything about LED bulbs in single beam halogen reflectors.
Single beam, dual beam, it doesn't matter.
http://www.candlepowerforums.com/vb/showthread.php?387680-LED-headlight-bulbs-illegal
http://www.candlepowerforums.com/vb/showthread.php?321214-Replacing-H7-Bulbs-with-LEDs
http://www.candlepowerforums.com/vb/showthread.php?377987-LED-H4-and-H7-bulbs-legality
http://www.candlepowerforums.com/vb/showthread.php?393807-H11-projector-bulbs-35w-HID-vs-LED
http://www.candlepowerforums.com/vb...Yes-another-LED-Headlight-conversion-question
I understand that HID retrofits and LED replacement bulbs may be unsafe if they aren't the right bulbs and aren't adjusted properly.
Are unsafe. There is no "right bulb" and no "adjusting properly".
I've seen both good and bad HID retrofits and LEDs.
You've seen all bad of both. The type of mounting precision, proper sealing *and* venting required, and a multitude of other aspects of "retrofitting" an HID projector into a vehicle it was not designed for means the chance of someone getting all of that correct is asymptotic to zero if not actually zero.
http://www.candlepowerforums.com/vb/showthread.php?380558-What-s-wrong-with-projector-retrofits
I installed good LEDs in my other vehicle and it works great.
They may appear to work great, but they don't actually work great. Your opinion of their efficacy is subjective, and our brains are easily fooled.
I know that there are so many cheap LEDs out there that aren't well designed and can be considered "toys" and that's why I was hoping for more information on the question so I could test it in my vehicle. If it doesn't work, fine but if it does I want to document my experience on what will work safely.
Then purchase a lot of testing equipment and the apposite SAE documents so you can perform objective measurements. Or send it all off to Calcoast ITL, along with a handsome amount of money so they can do the objective testing. Throwing these toys in your car, shining them on the wall and driving around a few blocks is not testing, it's playing.
As far as illegal, I've seen stock headlights that should be illegal, but maybe it's not the bulbs that are the problem but that they need to be professionally adjusted.
Many vehicles, sometimes even from the factory, could stand to have the headlamps aimed properly. However, the lamp assemblies themselves are legal and *can* be adjusted properly, and there are many options for safely replacing the factory bulbs with better-performing bulbs from Philips, Osram, Narva, Vosla, or GE (depending on the bulbs used).
Thus endeth that portion of this thread dealing with some of the whys and wherefores of the problem with HID "retrofits" and LED "bulbs" in headlamps.
Moving on:
Now we've got something to work with!
That Mazda 3 might be a candidate for new headlamps at this time, depending where you live, whether you park in a garage and have covered parking at work, and whether the headlamps have been damaged by abrasion from road grit/grime/salt and whether cleaning chemicals have damaged them. Sadly, the plastic lenses on modern cars degrade sooner than they really ought to. Since they may be a candidate for new headlamps, and since it appears that the 2010 Mazda 3 had a factory HID option, you could just get the headlamps replaced with new OEM HID headlamps at a competent dealership and have that snazzy HID upgrade you've always wanted.
If you choose to stay the halogen route, and also don't feel like the headlamps need to be replaced (be honest about their condition when you look at them. Even slight blemishes in the lens translate to a large loss of output and beam focus) then there are still some options. If you've never replaced those bulbs since obtaining the car, chances are they are of the "long life" variety. These bulbs are "functional" but not optimal when new, and as they age their lumen maintenance and the beam focus degrade. Beam focus isn't a strong point of a long life bulb in the first place, and the life on them is so long that they may appear to work (they light up!) you're getting far less light, and less-focused a beam than ever before. A standard bulb will burn out before they get so wretched; a performance bulb will shuffl off its mortal (filament) coil even earlier-- they're useful right up until the moment they burn out.
You may be a candidate for using the H9 instead of the H11 in your low beams (being a projector type headlamp it may have better glare control). For the high beams, replacing the 9005/HB3 with a 9011/HIR1 is a no-brainer. (Upgrading the low beams is trickier because low beams are where we're most concerned with glare for other drivers-- high beams aren't used around other traffic.) Both bulb swaps require trimming the base of the respective bulbs to fit either the socket or the wiring harness.
Speaking of wiring harnesses-- you might have voltage issues to address. Test your voltage drop in accordance with
this site. Good bulbs, with the right voltage, will make all the difference.