The coil-overs up front are adjustable. The rears don't appear to be. I am guessing that the little silver plug on the bottom of the reservoir is for assembly, if it was for adjustment it would probably have arrows with + & - . I can't see the top part of the shock, but I felt around up there and couldn't feel anything that felt like an adjuster.
Years ago it was popular to say that the factory shocks you got on new cars cost them about two dollars. I've always thought that the factory shocks were cheapos (besides for Raptor shocks) and I have always noticed a big improvement with the handling when replacing them. I put these on about a week before I put the swaybar on and noticed a big improvement. You're asking for an 'exact' difference between the cheapos and a quality unit. It sounds like you may be concerned there is a downside to upgrading your shocks. Everything about it is much better. I does not ride rough if that's what you might have been thinking.
With the addition of the swaybar I noticed the biggest improvement. I was kind of wondering what it was like to add the swaybar with the factory shocks, but that really doesn't matter to me. Doing both is what's best by far IMO.
And for the other guy with the 'what you pay' grammar correction....no worries.
Quick Overview (no mention of adjustability)
Dirt Logic Shocks with Reservoir by Fabtech are designed for the ultimate in performance, custom fit and the best quality ride available. They are built in-house by Fabtech at their Chino, CA (not China) facility using CNC capabilities, quality control and off-road design experience.
Another outstanding feature of the Dirt Logic shocks is the use of electroless nickel plating for the shock body. Electroless nickel will not deteriorate over time by turning milky and blotchy. Because of this, no clear coat is required. Nickel is the best plating possible for a take-apart shock. This standard is superior to other shock that apply a clear coat over zinc that eventually wears or chips off exposing the shock to rust.
Dirt Logic shocks are constructed using seamless steel tubing, billet aluminum top cap and rod end with urethane or spherical bearing mountings. Stem applications use a chromoly stem instead of the industry standard clevis adapter kit. A dividing piston is used to separate the oil from the high pressure nitrogen gas to eliminate fading and retain a consistent ride. This is superior to emulsion shocks that lose performance quickly.
The aluminum parts of the Dirt Logic are polished before the black anodized finish is applied. This results in a smooth surface for the anodizing to coat leaving a deep black luster.
External reservoirs are used to accommodate additional oil and nitrogen volume. The additional oil volume helps keep the shock cooler. The additional gas volume helps to keep more consistent control forces over a variety of temperatures.
For complete compatibility, Fabtech is the only manufacturer that builds both the suspension and Dirt Logic shocks in house. This guarantees complete compatibility. Covered by the Fabtech Limited Lifetime Warranty.