Before you all go run out and drill holes in your tunnels you might want to talk to a few of the guys that have tried this. It does NOT make your sled feel like a 2010 by any shape or form. Yes it is cheap...but it does not fix the problem. I tried this on my '09 and ended up bending the shock mounting shaft. It doesn't help the suspension transfer like the upgrade kits do. Sure it lowers the skid, but it also makes it so the shock can now bottom out (which is how the shaft got bent). It also does not help the sled carve. It honestly made my sled feel like it wanted to go in a straight line and not carve. I finally went with an upgrade kit and it completely fixed my problem.
Any of the kits out there work great. Doo's (only available for 154's), Xtreme Air Vents, Tom's etc.
Just my opinion and experience. I have a Tom's on one sled and an Xtreme on the other. Both work awesome!