I used plug-and-play replacement 9006 LED bulbs for low beams on my Suburban, and they were AWESOME. They were so clear, bright, and projected so well that I never used the high beams again. I got
AuxBeam brand from Amazon for under $40/pair, pure white light (no funky colors) and I aimed them properly using the stock headlight housings so as not to blind other drivers. The AuxBeam bulbs (and probably most drop-in LED replacements) have a heat sink attached to the back that takes up more rear-end space than OEM, but my Burb had plenty of open space available.
(EDIT: Just noticed on the Amazon page that Warehouse (used inventory) has them for $20/pair!! There is no reason I would NOT buy these right now, if I were you.)
See daytime photo below on my Burb. I took a side-by-side "garage door test" photo (cant find it now) of LED vs. OEM halogen, and the results were very similar to the car shown below... that photo pulled from the Amazon product reviews section. You won't believe the difference once you have them!
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I've love to put the same AuxBeam 9006's in my NBS Silverado dually, but it doesn't have clearance behind the OEM headlight housings for the LED heat sinks. I upgraded to Sylvania Silverstar Ultras instead, which are whiter/brighter than OEM but not nearly as good as LEDs. Plus more expensive than the Auxbeams, oddly enough. I do have AuxBeam H11 LEDs in my 2013 Traverse, which fit great and look/perform fantastic.