so my wife drives a 2006 lincoln zephyr, it is the same platform as the ford fusion, lincoln MKZ, and mercury milan. i bought the car about 2 years ago with 85k miles, it had a good set of matching coopers. a couple thousand miles later she got 2 flat tires in a week so i replaced 2 tires because 1 was ruined. about 7k later, around 95k she camplained of a noise. i tool it to my friends shop for an oil change and to check the noise. well the 2 coopers were shot and the 2 with 7k were worn causing the noise. i had them check everything including the alignment, everything checked out fine. so i replaced all 4 tires with a set of 60k mile yokahamas. since the last ones wore in 7k i decided to just have them rotated at every oil change. 4 oil changes later, about 14k miles, the yokahamas are done. nice even flat wear. so here we go again. everything is checked for problems and nothing is found, again. so on go a new set of 50k falkens. well we are 8k miles into this set and were on the same path as before, theyll in a few thousand miles.
i am getting kinda irritated to say the least. the shop is ran by a very good friend of mine and he has very mechanics who pay attention to detail and know i want it right. it is a second shop and the first is a suspension and alignment shop, very reputable. my dad does bodywork and we have looked this car all over and can find no signs of any accidents.

im at a loss, anyone got any ideas???