So my GS is a 2013 and the head lights just seem to be getting dimmer. I just swapped out my fog lights for these:
The light output from the fog lights is amazing. They really add some width and you can see things much clearer on the side of the road.

Now I want to upgrade my head lights, any tips? Any bulbs that are brighter then stock?

 

Those cheap LED bulbs don't typically last very long, the heat kills them.

For the headlights, it's probably time to change out the HID bulbs. Their outputs decrease as they age.

 

Any brand or bulb you recommend?

 

How about these?:

 

Just make sure that you're getting genuine bulbs, I wouldn't trust Amazon as a platform, make sure the seller is good. I'm sure there is another store that sells genuine globes although I can't remember it.

The Osrams are high quality but at 7000 kelvins you're decreasing your light output. If the primary purpose of your headlights are to illuminate the road, stick with the manufacturer's 4300K (I think).

 

Stay with either Osram, Philips or Morimoto for replacement HID D4S bulbs on the GS.

The best price will be for Morimoto $60/pair: https://www.theretrofitsource.com/d4...D4S?quantity=1
Philips next at $90/pair https://www.xenondepot.com/d4s-phili...402?quantity=1
Osram has a bunch of different D4S HIDs from $80 - $200 a pair.

Edit: Just realized you asked about "brighter." I think any HID bulb in the 4300k to 5500k range will be best...although most stock bulbs are 4300k and look yellowish at first but over time develop a white/blue hint. To the naked eye, a 5500k bulb will be more white/blue when first fired up on day 1 but may not have the same overall brightness...Osram claims to have solved that issue with diminished brightness from their 5500k+ bulbs so if you're looking for brighter, spend the $$$ and give the Osram Xenarc 5500k bulbs a shot.

 

If you want the brightest, stick with 4300k - 5000k. Any higher, then you'll lose functionality.

I changed out my bulbs to these, OSRAM Xenarc Night Breakers since they are the brightest bulbs that you can buy. I have zero regrets. They're pricey but are well worth the money.

If you do your own research on these bulbs, you will find that these will always rank at the top.

Link with a price: https://www.hidconcept.com/products/...ulbs-pack-of-2