Initial impressions on the coils? They're fantastic. They got rid of my sag and even gave me a bit of rake. That's with about 650 lbs in the back. I have an OVLRND campers pop top, empty just 2 wood benches I built inside, no gear I only carry gear when I hit the trails. A full 37" spare and Rigd carrier. No more sag, not overly stiff, they ride great. Definitely a bit firmer than Thuren, but that's exactly what I was looking for and expecting. Overall I'm very happy. The Thuren was great, but since I have all that stuff in the back now, the Thuren is no longer able to handle the weight as it wasn't built for that.
The sway bar I HIGHLY recommend only if you have a camper or rack with a tent up high. Otherwise, I see no need for it. I was getting terrible sway back there with the camper and super soft coils. I had installed the sway bar first before the coils, and already there was a huge difference in sway reduction. I got the big wig, the biggest size they offer. It comes with adjustable end links that I trashed. They are absolute junk. I already had Thuren HD rear end links which are longer and beefier than the Hellwig anyway. But if I didn't have the Thurens, I would have still trashed the Hellwig ones until I ordered the Thurens. If you do get the hellwig do yourself a favor and get Thuren's end links for the rear. The adjustable one from Hellwig is just a long piece of threaded rod female and male, and some basic bushings. Build quality is crap and so are the boots. They're also thin diameter and I wouldn't rely on them if you off road your vehicle.