Rear wheelhouse liners are plastic liners which protect the inner wheel well for the rear wheels. They used to be standard, but for some reason they are now an option for all trim levels except apparently for Longhorn and Limited models. Since I was shopping for a Rebel or a Laramie I wanted to make sure to have those on the truck I was looking for. They aren't very expensive to add later, and only a small pain to install yourself, so they weren't a deal breaker.
I notice a huge difference between the halogen projector headlights I had on my 2017 Rebel, and the LED's on my new Laramie. Definitely worth upgrading if you're thinking about a Big Horn. They're standard on the Rebel and Laramie so I only needed to worry about those when I was looking at Big Horn models.
I used to make fun of people who wanted heated steering wheels. But now I understand why people like them. In fact, if I had to choose btwn heated seats OR heated steering wheel, I'd chose the steering wheel. And I like the other "crap" I had to get in order to have it.
I haven't driven a 5th gen with halogens, so I'm not exactly comparing apples to apples. But I had two different 4th gens with them. One had halogen reflector housings and one had halogen projector housings. Both sucked about equally. I drove my daughter's 2019 Rebel when she first got it (LED housings), and the difference between hers and what I had at the time was literally night and day. That's why I wanted LED's. Sure, for now LED bulbs cost more, but like all new tech, that will pass as they become more mainstream.