That is strange. I have a Baja rack with recovery gear ( High-Lift, Angry Beaver Shovel, and Axe) and a 34" spare on top. SSO bumper with Stage 2, 34's and sliders and I get 283 miles to a tank and I run 70-75 all day on the highway.
Had this kit on my T4R a few years ago when it was under factory warranty. Toyota didn't cover the rear shocks because they were replaced with Revtek ones. Everything else was fine. The added spacers on top of the struts didn't change anything as far as Toyota was concerned per the factory...
XO-Fab.com makes them. I bought their DYI weld on sliders. I changed my mind about welding them on and contacted them about brackets. They said they were in R&D back when I first reached out in April. Well, I have a set now, ordered 3 weeks ago and they took 4 days to show up. They wont show up...