Yes, the design does cause some HP loss.

And you go looking for a drop in rpm when applying carby heat in most piston
engined aircraft.

Should apply just as much to diesel engines as well based on the performance
difference in my old 4.6 ton underpowered non-turbo diesel truck that goes
like a rocket on cold mornings, and that it can't even get up to 50 mph on
the open road on a summer afternoon.

However many systems also use unfiltered air and this provides a difference
again. The same old truck has a ram air system made from a plastic kitchen
container that "force feeds" the air via a 100mm stormpipe to the air
cleaner system. It makes a difference in "performance" but nowhere near as
much as the four foot high, seven foot wide, tailgate loader that sticks up
at the back like a dirty big air brake!

Depends on where you operate, filtered air does provide some protection to
the engine, and ingestion of dust can cause sudden engine problems.

Hope this helps,
Peter