Autoride is an electronic system that monitors vehicle dynamics(speed, acceleration, deceleration, squat, lean...) and adjusts shock firmness accordingly. All 4 corners will have sensors and electrical connections to each of the 4 shocks. Along with that, the rear shocks will have air bladders along with an air compressor to maintain ride height at different weight loads(passengers, gear/stuff, towing...). Most find it a love/hate relationship, it works well but is expensive to repair and eventually, it will need to be repaired. It also limits how far the rear can be lowered.
You can replace with non Autoride shocks, but you will lose all benefits of the system by doing so, if that matters to you. You will also need to take measures to disable the Air Suspension warning in the DIC, again, if that matters to you. The Bilsteins are also a love/hate part, some feel they're fantastic while others say they are too stiff. However, I do believe most of those reviews came from 1500 series truck owners, I don't know if the 2500s had stiffer shocks to begin with.
If you're just looking to replace shocks and/or a mild drop(up to 2" front/3.5" rear), really, I like the Autoride and would choose to keep it, I did on my 05 Suburban. If you're wanting to go lower, than bypassing Autoride is a necessity.
GM now offering the Factory Service Manual as a subscription?!?