Here is my 2 cents about these parts and how install went. I just recently installed 5100 and all four corners, eibachs, wheel spacers, and AAL. I took it to my dad's warehouse because my uncle has basically put in a pro garage in the back. He has a lift and air compressor which made install go much smoother. Everything was pretty straight forwards thanks to some awesome write-ups by other members! Wheel spacers were real easy to intall. We did run into a few problems though. When we were compressing the first eibach of the 5100, the spring compressor got stuck between the coils and we couldn't get it back out . There are a few more coils in the eibach coils than there are in the oem coils so if you are sticking with stick coils you should be alright. We ended up taking it to the local tire guy and they got the compressor out for us and put the other shock together as well. After all the parts were on, took it back to the local shop and had them put my new tires on and do a front end alignment. I noticed 5 miles down the road that the front right shock was acting funny so i pulled over and looked at it. The shock that the shop put together was shooting through the housing! No bueno. Took it back and told them that they didn't assemble the shock correctly and luckily I had the piece that they "missed". Thankfully they fixed it with no hassle and now everything works the way it should.
IMO, the ride has improved greatly! It a bit of a rougher ride (probably due to the eibachs) but I like that so it doesn't matter to me. I don't know how it has affected my gas yet, but as soon as I know ill give ya'll an update.
Really easy WITH THE RIGHT TOOLS! A buddy or two also makes a huge difference. If I ever do 5100's with eibachs again, I will probably have a shop put them together.
I would do it again in a heart beat. It has completely changed the way my truck looks and I love the way it drives now.
Thanks for letting me rant lol I just wanted to share my thoughts with everyone and hopefully answer some questions for future reference