Storage capacity under the Seats.

Do any cars have storage capacity under the passengers
seats?

If yes, is it comfortable?
If no, is it feasible?

In the US the Ram trucks have storage under the rear seats. There's minimal/typical space available under the front seats, but there's also wiring and thermoelectric devices under the front seats so storing items under the front seats would not be recommended. But it's designed for under the rear. Additionally, there are storage compartments in the floor under the rear floormats as well.

The underseat storage does not seem to affect passenger comfort at all, and the cushions are still pretty thick. My Ram even has heated rear seats, but that doesn't require a thick cushion, it just adds to the comfort level.

I use the storage space to keep an portable jump start pack, the charger for the jump start pack, and a few miscellaneous hand tools.

-Rod

As far back as I car recall, every vehicle I've owned had storage under the seats.

It's a great place for that missing ice scraper, books of matches, that glove you couldn't find, shotgun shells, coins, extra drinking straws, and all sorts of items that can't fit in the glove box or console. It's all perspective.