I was looking at that myself along with what could void a warranty when I started to want to upgread mine... All ford ST's are sold with a 3 Yr 36,000 mile warranty... You can extend it if you wish.. Here's the link to ford's warranty info..
Uneven wear in the tires. Mine are on the inside of tire. I'm glad I found this site has helped me alot. Very knowledgeable here. Check suspension and handling forum.. Good luck Paul