I just saw where the tires are 275/50R22 and the spare is 265/70R17 for the Ultimate. Being new to GMC, why would they not give it a matching spare tire size? If I am paying all this $$$, I want the spare to be the same size so if I have to change it while traveling, I will at least feel even. Also, who make the tires that come with the Ultimate off the build line? It is generic black wall tires on the website I saw. Do any of you more seasoned Yukon owners have a preference to which tires are on the Yukon? Would you keep the ones that come with or change/upgrade to a different tire?