If you try aftermarket bulbs and the beam pattern is wrong, or you have serious aiming issues, then it might be a because the bulb base does not fit the apparently non-standard Mazda housing and the bulbs won't stay in place (I couldn't use Narva bulbs, and had to revert to the OEM Mazda bulbs).
The 2008 and several earlier models lack the fog light adjustment, as noted. There is the noted vertical adjuster for BOTH hi & lo - it is the only easily accessible adjuster, and it's the one that has the white plastic right-angle clip attached.
After you set the height of the entire assembly based on the high beams' adjustment, then you need to adjust the low beams' height afterwards. There is no independent high beam vertical adjuster, which drives mechanics nuts unless they know that. Most don't. Adjust left/right if necessary, and recheck up/down for each.
In other words, except for the missing fog light and the corresponding fog light adjuster, the assemblies and adjusters are EXACTLY THE SAME for all of the Mazda 6 first generation cars, up to and including the final 2008 model year. The only differences during the run, other than the fog lamp, were cosmetic: the color of the lens (not where the light goes through!) and the color of the visible "interior bottom," the ridged or corrugated plastic section under the reflectors (champagne to black).
mrQQ, I think you didn't look at the right adjusters.
Here are my estimates of the measurements needed for determining proper aim, per Daniel Stern's webpage directions:
Height of lamps' center axis: 27" from ground.
Distance from centerpoint of car to center axis of high beams: 20" L/R of center (40" wide).
Distance from centerpoint of car to center axis of low beams: 30" L/R of center (60" wide).
Distance from high beam to low beam: 10".
If someone has better measurements, please note them!
I had to have one entire headlamp assembly replaced after it was damaged in a small collision. Make sure the body shop knows how to aim the beams, or you'll have serious problems. They need to aim them before they reassemble everything and they need to do them in the proper order! The headlamp assemblies do NOT come pre-set for even close to proper aiming. And many mechanics seem to avoid using the proper hex-keys, and can damage the adjustment screws by forcing a phillips driver into the teeth of the adjusters.
If you do need to replace a headlamp assembly, save the white plastic right-angle adjustment clip from the old unit if you can, and put it on the new lamp assembly to ease your aiming adventure. If you want to order more of the clips, they're Mazda part #GJ6A-51-0K4. About $20 each from Rosenthal Mazda or other online dealers, which is far cheaper than getting them over the counter from a local dealership. It is absurd that Mazda didn't put the little clip on every one of the adjuster screws. It probably costs them all of 10 cents, and a $550 lamp assembly should come with all the needed parts to allow the lights to be aimed correctly and easily. I now have these clips on all of the adjusters, except for the "B" for the horizontal aiming of the low beam (that's the adjuster that's hardest to reach, and the one you will have a hard time getting the clip onto). To adjust each setting, all you then need is a 6mm hex key (get a long one with a rounded end). To get to the under-fender "B" adjuster, onto which I couldn't get the clip to attach even after scraping my hand bloody on the inside mounts for the fender, I use the ratcheting bit wrench described below.
OK folks: here's the important news.
There are many "bit ratchets" that will let you access the every single one of the adjusters. There are several versions available. This style of bit wrench will work for ALL of the adjusters, even the under-fender "B" adjuster, without any need to pull the bumper, fender liner, or remove ANYTHING in the engine bay.
The first one shown below is a Husky that's commonly available (and cheap) from Home Depot. Most of these bit ratchets are made in Taiwan; they're available from Geodore (shown next to the Husky), Gearwrench (shown is a set you can get from Amazon and Sears; the handle is about 1/2" longer than the Husky), and other companies like VIM. You can also find a far more expensive bit wrench from Wera, shown last. All of these are very small - usually under 5" long. You put a standard 1/4" insert bit, with a 6mm hex end, into the business end of the bitholder. Get a set of metric hex key insert bits (mine are from Wiha, #71397) and you're all ready to aim. I suggest adding a temporary wrist lanyard to the non-business end of such a tiny ratchet, so if you drop it in the engine bay you will be able to retrieve it easily.
Although Bondus ball-end hex keys are common, here's a great set of Wiha ball-end long hex keys, and another excellent set from Wera (the long key with a ball-end is what you want to use on the adjusters you can reach without needing the insert bit wrench):
And the easy way to make sure the car is centered on your measuring wall is to use a laser level. I sat this Bosch laser on the center of the dashboard - worked perfectly.
MODIFIED MARCH 2012.