When we read about an enhancement, the first thing that comes to mind are better graphics, sounds and so on.
That’s not the case at all.
X-Aerodynamics decided to focus, for once, on the core of the simulation, enhancing the flight dynamics and creating another two versions of the default C-172.
All of the three aircrafts (C-172S, M and R) share the same base, which is an high level one as the default Cessna, and are tuned to reach a performance accuracy of 99.5%, as stated by the developer.
X-Aerodynamics has researched and prepared extensively to develop the most accurate and thorough C-172 flight dynamics yet seen for desktop flight simulation. For example, everyone knows that the Cessna 172 uses a NACA-2412 airfoil for the main wing, right? Partially right, partially WRONG! Early Cessna 172s did, but from the C-172M onward, Cessna introduced a modified profile, which it marketed as the ‘Camberlift wing’. You can see the difference on the real aircraft as the later versions of the wing are much thicker and more blunt at the leading edge. The performance of the ‘Camberlift wing’ is modelled accurately in this add-on.While the stock C-172S is very good graphically, audibly and so on, the flight dynamics have some limitations. As can be seen on the comparison charts, performance relative to book numbers is not always a good match.Beyond just book numbers, however, there were some other errors in the flight model that affected handling in ways that may not be obvious. For example, the entire tail was positioned too low, probably because C-172s tend to sit tail-low on the ground. In reality this is due to flex of the landing gear, the horizontal tail is actually in-line with the waterline of the bottom of the side windows. This and other areas were addressed with the new EFM flight models. Why is this important? The position of the tail will affect how it interacts with downwash from the wing, fuselage wake, propwash, and even ground effect in the flare!New airfoils were developed that match reality and polars were generated for Reynolds numbers across the range the C-172 may encounter, maximizing realism of wing performance at all speeds

X-Arodynamics has also released a feature list that you can read below.
Improved ground handling, with ‘springy’ main gear, as in the real aircraft.
Cruise speeds accurate across all altitudes and power settings.
Accurate maximum speeds.
Accurate stall speeds, flap up or down.
Correct rates of climb.
Accurate take-off and landing distances.
Accurate feel and handling.
Accurate fuel consumption at all altitudes and power settings (if properly leaned!).
The package is available here for $19.95.