Spur gear chassis cut out's

[T17]

Hi All

I've been looking at the TLR 22-4 and the Schumacher Cat K1 Aero as possibles to get back into the sport.

The one thing that surprises me in both cars is the chassis seems to have a cut out for the spur gear (well the cat does not so sure about the 22-4 - some photos appear to show this). Surely this is exposed to harm or dirt egress.

Any experiences/thoughts. Is this a problem?

Thanks