Trunk comparison: Audi A6 Sedan vs Skoda Superb Wagon

Key Differences
Significant differences are mainly found in the geometry of the trunk opening and the loading edge: The height of the Škoda Superb Wagon's trunk opening is 12.6 in (64%) higher than that of the Audi A6, and the width of the Superb's trunk opening is 4.7 in (13%) larger.
The Audi A6 has a trunk depth (loading edge to trunk floor) that is 1.6 in (50%) greater, while the Audi's loading edge is 2.8 in (12%) higher above the ground than the Superb's.
Smaller differences (under 10%) include: the Superb is about 7.1 in (9%) longer with folded seats, the Audi has about 3.5 in (8%) more trunk length with the first row of seats upright, and at the narrowest point only ~0.4 in (1%) more width.
Impact on Usability
The significantly higher and wider trunk opening of the Škoda makes loading bulky, tall, or wide items much easier – for example, large boxes, furniture, plants, or bicycles can be maneuvered and tilted more easily. The lower loading edge of the Superb reduces the lifting effort when loading heavy items.
The Audi A6 offers a deeper cargo well due to the greater trunk depth, which can be advantageous when stacking flatter items or carrying longer loads lengthwise.
However, the higher loading edge of the Audi increases the effort required to lift heavy loads and makes sliding very heavy objects more difficult. Additionally, the smaller opening height and width make inserting bulky or voluminous cargo more challenging.
In short: Those who frequently load tall, wide, or very bulky and/or heavy items will benefit more from the Škoda Superb Wagon.
Those who make more use of the deeper cargo floor (e.g., for stacked, flat, or longer items) and prefer the slightly larger interior coverage may find advantages in the Audi A6 — although with somewhat higher effort when loading due to the higher loading edge and smaller trunk opening.