Trunk comparison: VW Caddy Wagon vs VW Touran

Key Differences
The VW Touran offers a significantly longer cargo space when the seats are folded down: +24.8 in (54%) compared to the Caddy Wagon.
Conversely, the Caddy Wagon has a considerably larger trunk with all seats upright: +28.7 in (215%) compared to the Touran. Furthermore, the trunk opening of the Caddy Wagon is +11 in (33%) higher than that of the Touran.
Another notable percentage difference is the trunk depth (loading edge to trunk floor) in the Caddy Wagon, which is +0.4 in (100%) greater; however, this absolute increase is practically very small. The other measurements (e.g., +2.4 in, +3.5 in, +3.1 in, +2 in) are under 10% and comparatively minor.
Impact on Usability
For transporting long items with folded seats, the Touran is the better choice: the 54% longer loading length makes it easier to carry longer, straight cargo such as slats, pipes, or long furniture pieces.
If, on the other hand, you often travel with full seating and still need to carry a lot of luggage, the Caddy Wagon is more advantageous: its trunk is 215% larger with seats upright, offering significantly more usable storage space for suitcases, shopping, or luggage without having to adjust the seats.
The 33% higher trunk opening of the Caddy Wagon facilitates loading tall or bulky items (e.g., boxes, equipment) because there is more vertical space available without edges or protrusions. The nominally greater depth of +0.4 in (100% in percentage terms) is hardly noticeable in practice and barely affects usability.
Smaller differences such as a slightly higher loading edge in the Touran or marginally narrower spots in the Caddy are secondary for most users—they only slightly affect daily handling (easier lifting in the Touran or slightly less pass-through width in the Touran/Caddy).
In summary: Those who primarily transport long cargo with folded seats should choose the Touran. Those who frequently travel with full occupancy and still need to load a lot of luggage or bulky items, or who benefit from a higher trunk opening, are better served by the Caddy Wagon.