I believe that guy doesn't know what he is talking about. The SR5 doesn't come with any sort of "special" suspension, just your basic shocks and coil springs setup. You can throw any sort of leveling/lift kit on your rig without issue. The only thing that can go wrong is an incompetent tech breaking one of your ABS sensors while doing the installation. That will for sure light up your dash like a Christmas tree. I'd avoid 4 Wheel Parts for sure.
This was my initial thought, Good to know.. So far this forum has provided me way more useful information that 4 Wheel Parts, i'll be going elsewhere to get suspension work done--and quotes. Thanks man, really appreciate the guidance.