With the 144" tunnel you can't even get away with a 151, it will eat your snow flap.
You can put rail extensions on it as well as a tunnel ext from say SLP and go clear to 166 if you want. I did this on an '02 Edge chassis.
The '05/'06 900 skid is a direct bolt in to the Edge, you just have to make sure and get your mounting locations set correctly, not a big deal.
To run anything more than a 2.25" track in the edge you'll either have to change drivers or drop/roll the chaincase.
In my opinion, unless you are doing a motor mod on the Edge, the 166x2.4 track is not a good option. Motor mod, sure. I ran mine with a 910 Carl's Cycle big bore.
sled_guy