I don’t know for your specific model, but flashy aftermarket housings are notorious for having worse headlight beams than oem.

If you truly want best possible, that’s probably a projector retrofit. You can diy for about $500 (+headlight housings) or pay specialty shops around $1500 for a basic retro. This puts a projector pod (no, not some LED flood light, an actual headlight unit) inside the plain housing.

If you have the 99-07 style Sierra with a 9006 low beam, 9012 bulbs (and wire cutters to trim the tabs) is a reliable bet. Same wattage, but an infrared coating nearly doubles the lumens. It’s a shame these didn’t stick around. If it’s the 07+ style with H11, you could consider an H9 as long as the low beam has a glare cap. It’s a higher wattage bulb, but not by much. 65w vs 55w I think. It doesn’t seem to be more than the housings can handle, typically. Could be more than 30% more light. No idea what your aftermarket set has though.

Aside from that, there’s not much that actually improves headlights, assuming they’re in good condition (lenses and bulbs). People love throwing HID/LED bulbs in there and think they’re so cool, but they actually suck. Majorly. People get wowed by puking light in the first 50ft. That does jack squat at 40mph. It’s hard to gauge how well light throws down the road, so they don’t notice the drastic reduction in sight distance. Meanwhile, it’s guaranteed that the beam is now glaring at every other driver. No, you cannot just aim them down. Not if you understand anything about glare, hotspots, or beam distribution. You want good coverage across the beam, a central hot spot at the very top of the beam to throw way down the road, and as little glare as absolutely possible. But people are naive.

I personally think OEM quality replacements are the way to go but there are high-end kits (~$700+) available aftermarket that can give you modern stuff like projector lenses and animated signals/DRL strips but a lot of them look really tacky too. I went with TYC stock replacements from RockAuto for my '07 classic (cat eye) and got everything for around $150

FWIW, Rock Auto has some of the cheapest options you’re going to find if you want the factory look. Just looking for ‘2007 Sierra’, I’m seeing $90 to $200 per side. I’ve bought 4 sets from them now (4 different vehicles) and I’ve always been glad I did it afterwards.

Be sure to take the time to aim them afterwards.

Depo and TYC make good quality OE-style aftermarket housings. My Sienna has a set of TYC headlight and taillight housings, they are indistinguishable from the (broken) OEM Toyota housings they replaced (headlight surrounds are black, but that’s the only difference).

Look around local junkyards as well, you can score a set of OEM housings for cheap. Might need to be polished, but if the price is right…

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