yep, as mentioned, the air compressor is for the tires. it's also to inflate the spare because it's stored deflated (the sidewalls fold in making it more compact).

as for the rear fog, in our case it's not for visibility on our part. it's actually for visibility for others. i always flip it on in adverse weather. it's nice knowing that people will see me a bit sooner than anyone else.

when we have it on, it basically looks like the driver side brake light alone is lit up. in the C230, the rear foglight sits inside the brake light assembly.

and yeah, like isp james mentioned, here it is on the integra as a seperate assembly: