Suspension Noise problems of the 2004 Mazda MAZDA6

My complaint concerns the following issue: in the summer of 2006, this car began to exhibit occasional clunking and grinding from the front suspension during low speed maneuvers. I took the vehicle to montgomery Mazda in charlotte, nc, and tim marburger Mazda in concord, nc, for diagnosis. During this time, the car was under warranty, and had approx. 41,000 miles on the odometer. Neither dealership could duplicate the problem. ? in late August 2007, this car began to exhibit continuous clunking and grinding noises emanating from the front suspension during all driving situations. In early September 2007, I took the car to montgomery Mazda in charlotte, nc, for another diagnosis. I was told that the issue involved spring isolators and bushings in the front suspension, and repairs would run approx. $480. 00. I inquired about whether this item was covered under recall or warranty, and was told no. ? on September 26, 2007, I took the car to a local mechanic near my home, who verified the diagnosis from montgomery Mazda. He called the dealership to inquire about parts, and was told that spring isolators, bushings, and other parts to correct this problem had been redesigned, and that they had been issued new parts numbers. Given the fact that I brought this matter to the attention of my local dealers while the car was still under warrant, and given the fact that the redesign of these key suspension parts indicates a clear, known defect in materials and/or design, I am asking that Mazda cover the cost of repairs on my car.