Superduper, I don't remember what the stock sizes were. Originally I think the price was around $320.00, but when they arrived the dealer told me $550.00 and ended up reducing the price $50.00. As I said he really didn't have very good knowledge of Unverferths product and probably didn't communicate very well with Unverferth about pricing either. Anyway even though they were more expensive than I initially thought. I was pleased with the quality and precision of the extensions. I think a stock size was a 6 inch extension which at the time I felt was too wide. Now after putting 200 hours on the tractor, I probably would have prefered 6 inch extensions for even a little more stability. The only problem with going that wide is if the extensions make your tires extend out wider than your loader bucket or a rear implement.
Clayton, that was also my feelings about the price of the extensions, $500 was cheap compared to a possible rollover. I'll try to take you a pic of the tractor from the front, so you can see how the front tires line up with the rear tires.
Sincerely, Dirt