I have long been of the opinion that rotating tires on FWD will cause problems and on RWD cars may cause problems. I have had General Grabber AP tires on a large 4x4 before and had no trouble, but I did not rotate. As to prices, with all the tire companies buying each other up, there is no competition left and prices are going up double digit percentages each year. I keep hearing the pre 2000 MLs are suspect. Sorry to hear you are having trouble.