Another option (probably a lot less complicated and cheaper) is to buy high intensity lights from ebay. I don't know about the GLA halogen part number (I have the factory bi-xenons) but there are replacement bulbs, ballast set, and resistor packs available on ebay for most halogen replacements for around $50. You also have the option of choosing the color (anything below 5,000 is similar to OEM, anything above 5,000 has a bluish tint).
They are not as nice as bi-xenons but definitely much better than halogens.
I did this for my truck 6 years ago and had to replace the bulbs after 4 years ($35/pair). The installation was pretty easy and I just had to drill a hole in the light box to feed the additional wires through.
On my truck, there are separate bulbs for low and high. With the high intensity bulbs installed for the low beams, I never need to use the high beams. So, they are that good!
The glare depends on the wattage you use and also your headlight adjustments. I installed 35W bulbs and they are not dazzling at all. My guess is that you are thinking of off-road bulbs that some truck owners put on their trucks. Those are around 55W bulbs.WOW am i glad i don't live anywhere near you!!
There is so much more to a xenon setup than just banging in HID replacements for regular halogens.
dazzling glare will be a huge problem for everyone you drive at.
Rayman, no i wasn't talking about the dynamic range adjustment.Time, if you are talking about "dynamic headlamp range adjustment" to avoid dazzling oncoming traffic (which comes with the GLA's bi-xenon light setup), you won't get that with the $50 setup