I love mine to, like you said, It might not do 70mph, but it just crawls through anything in Diff Lock, it might only do about 5 mph :cheeky4: in diff lock/super low, but the torque that it has in that gear is amazing for a 300, pulls like a beast, it can go anywhere my buddies sportsman 500 can go and then some more, except up hill. it doesn't have the power to go up hills the sportsman can.
As for the tires, im not sure, they aren't stock, thats all I know, if i find out what stock size is i'll post it up, should be the same as any other 300 king-quad, so try looking for specs on like a 1999, basically identical, except newer ones have round headlights, but the older ones are rectangular.