tunnel cooler
I have a rear tunnel exchanger on my 13 Pro,w/163 track.I bought mine from PAR. It works some but I do see the temps climb pretty fast. I even tried a longer snow flap. I have a Brandt bag on my tunnel,maybe that's keeping some of the heat in. I did change my ice snatcher's to the newest design of cable ones. I'm going back to the regular ones that came with the sled. For me and my sled if your not in deep snow you see the temps rise.
If still interested talk to Brad at PAR