Sorry to bring up an old thread but I have some input on lower back pain from lowering your truck. Here's my experience. Before my XR I had a 2006 CCSB Silverado and I dropped it 5/7. Needless to say the frame sat on the rear end. I wasn't expecting this to happen, I was inexperienced at the time. Well I drove the truck like that for over 6 months. Not only did it rattle my truck to pieces but I started having a dull ache in my lower back which progressed into me not being able to even get out of bed or put my pants on alone. My wife had to put my pants on for me, my shoes, wash my feet and legs. I couldn't bend over without being in excruciating pain in my lower back and radiating down my legs. I decided to see my primary doctor who referred me to an orthopedic office. The orthopedic dr sent me in for an MRI and found that I had Inflammation in my L5 pressing onto my S1. Ever heard of sciatica??!! Keep in mind I was 22 years old at the time! Healthy, fit, young man now nearly crippled by this damn inflamed disc. Now here's the kicker: I only had a dull ache in my back when I finally decided to notch the frame. That dull ache progressed into full fledged incapacitating pain, Lon after I completed the notch. This is because the damage was already done, and just working as I normally would complicated the issue. This is a pain I still carry around at times. I was told that it will always be a weak point in my spine.
Moral of the story: if you're gonna lower your truck, notch the damn frame!