Ski carbides need to be removed and replaced with regular steel wear bars. Your stock track will be fine for getting started. Studs are almost a necessity, and chisel points are best for grass. I've found through trial and error that it doesn't pay to skimp on the proper parts. Any edge that you can gain on your competition will move things ever so slightly in your favor.
Every little thing adds up in the long run.
A means of cooling down your sled between runs is a must. To do this, you will need to build a cool down cart. All of this fits nicely in my kid's wagon. The thermostat is removed from the snowmobile to allow the water to flow throughout the system. Then, a set of quick connect couplers is added in one of the hoses under the hood.