The iron dog is long and I would say harder on the driver than machine. If you were to put on 1500 miles on a 25 mile lap track, your machines would not survive well. Light conditions also mean everything. I assume that the iron dog is run with mostly headlights which saves plenty good on the machines. the pros ride the sleds to the end, what ever the failier that stops them. I think polaris has made good improvements in one year for what they started with. The two top polaris sleds were iqr's in the 500. I dont know what Cory Davidson was riding in the Soo. If polaris wants to improve the rush, stop production of the iqr. Make them race it and it will get better in a hurry.