Tomorrow is the last day I can make changes to my combine order. Think I will up to the 9120 so I have plenty of power to run the Magnacut in my sometimes tough irrigated wheat, peas and canola. Question is should I get the ST rotor or the AFX?? Is the ST harder to control rotor loss in dryer conditions and/or not full capacity dryland crops? Is the extended wear rotor worth the price?