I ran 33" swamper radials on my 99 TJ with 3.73s and didn't notice a significant power loss. I had 2" coil spacers and a 2 inch body lift and had no vibration problems what so ever. Right now i run 35" Toyo Open Country MTs on my duramax and i honestly won't run any other tire. Their durability is amazing - i have over 40,000kms on mine with and they don't even look half worn yet. The secret is rotating them religiously, i do mine every 5000-7000 kms. As for winter traction on snow and ice, in my experience they are equal to a BFG All-terrain (which is my bench mark for winter tires as they stick like glue no matter how icy the roads are). I am extremely impressed with their poor weather traction and low road noise. My next set of tires for my YJ will be Toyo MTs.