CarrotRentals,
Larger diameter tires will cause some loss of power.
There are some forum members that increased the tire diameter by two inches. As I recall, the two additional inches led to tire rub. These issues were not on the new models. Just saying to research the tire size issue to ensure you are happy with the decision.
Also, I have the ATV tires on my 900. For me they work great because I don't have to deal with much mud. I'd suggest purchasing an aftermarket tire that will likely last longer and be more aggressive. Of course, the aggressiveness has its downfalls of tearing up the grass or ground leading to erosion.