The MeisterR won't be too stiff, the valving are design to keep ride quality compliant.
And the Koni + Ground Control will get no where near the low of the SuperLow.
If you do not want to go more than -75mm, I recommend getting the standard Zeta-S.
They are better performing, and also slightly cheaper.
The dual perch design will make sure suspension travel are maintain and ride remain good over uneven road surfaces.
The package come with everything including new top mount, and a 1 year warranty.
If you are sure that you want to lower more than 80mm toward and over the 100mm area, then the SuperLow are design for you.
Ride quality will remain acceptable, but the range of height adjustments will be low, really low, and super low... low to the point where you cannot get the car off the drive without removing the front bumper (as it happen to one of our customer).
So it depends on what you are after.
But we design a few different version bespoke for owners with specific need.
Because while the MeisterR suspension can take care of a wide range of role, hardware changes that are necessary sometime in order to achieve a specific goal.
If you have any other questions, please feel free to let me know.
Jerrick