Superman
TY 4 Stroke Master
I might close mine soon. My last 60 mile ride produced solid Ice on the tops of the running boards. Only way I could break it off during the ride was with a screwdriver. Plus all the ice on the bottom of My bibs. I've talked things over with a few friends about bikes and 4-wheelers, Summer vs. Winter and our thoughts are, We really don't see it melting anything. I just feel its time to try it. I love the sled so much and this water/ice issue is the only bitch I have. The Yamaha gaurds don't solve the problem from My experience either. I'm going to take a guess that the hole is going to be changed on the 08's or removed all together.
phazerboost
Pro
MC-X supplies a filler panel for the hole in the tunnel and I have not had any problems with melting plastic. I will tell you not to close off the hole under the fuel tank though. I tried that and covered the exhaust in header wrap and stuff still got too hot under there, hot enough to burn your hand on sub frame and start to melt zip ties.
At first I completely closed the back of my tunnel off, It seemed to run hot but did not melt any of the plastic, I cut a piece of diamond plate 24" long and used the front two bolt holes of the storage trunk to start, then ran it all the way forward it just covered the hole. I bought the piece of aluminum diamond plate from menards and had to trim a couple inches off of one side. It fit perfectly on top. I then drilled five more holes in a row and bolted the aluminum plate to the top and hyfax underneath for tunnell protectors (I put the flat sided of the hyfax against the tunnel and the bolt head fit in the channell). I cut one piece of hyfax in half and ran it on each side in back. I'm running 144 bergstrom trail grabbers. I used 1" long 1/4 inch bolts with lock nuts and it worked very well. Sorry I don't have pictures. After the first day of riding, I did take the plate back off and trimmed 6" off the front of the plate, It opened the V shape in the tunnell to let more air flow in and not much snow, but seemed to run a little cooler. I think it worked very well and I am pleased for now at least I think this is a comprimise. Very little ice and water build up, I have run the phazer on 2 hour rides with no stops, I have 450 miles on the phazer with the rear tunnell partially closed. 850 miles Total. The first 200 miles were 35 degree days, It wasn't ice that was the problem, but all the water running down the tunnell and into my boot. That is why I closed my tunnell. I also ran a 1/4" bead of clear silicone from were the aluminum plate stopped all the way to the front and all along that rubber seal to the front of the tunnell to help keep the water in. Sorry for so many words. 
