I had my BFG MT's siped. I think they only charge about $12.00/tire at Discount Tire (they did mine for a bit less 'cuz I had them siped when I bought them). I've used MTR's, Maxxis Big Horn, and BFG MT's un-siped, and so far this has been the best in the snow (we got dumped on about a week and a half ago). I was worried that the tire would be more vulnerable to damage off-road with the siping, but I did a trail a couple of weeks ago and the tread is still very intact. The only sipe the center blocks, so the tread block on the edge that might be more susceptible to damage retain their integrity.