You can see the exhaust in the first pic i posted, snaking down, bending around the steering column and under the starter. It ends up through the belly board (skid plate) with the silencer just above the plate. There isn't much heat coming off the stainless exhaust, except for the first 2 inches, so I don't think there is a need for fireproof sleeving.
I see that I posted that same pic again in my second pic-post, and in the 2nd to last pic you can see the flexible exhaust pipe coming out at the front of the heater and bending around to point back- and downwards.
There is a (needed) silencer on the air intake as well (on my 2 overview pics, between lhs battery and wing). The heater is quite noisy, like a small jet engine starting outside the house every morning.