I'm having tire issues.

I'm not excited about dropping 150+ on each tire so a buddy has a spare pair of Falken Azenis ST115s. I read reviews and they are supposedly a great tire for less than 90 new.

I currently have a set of BF Goodrich Traction T/A with less than 10k miles (2 yrs old) and they are ripping at the sidewall up front. Anyone else having a similar issue... tire pressure, suspension, alignment all checked out fine. They are within BF Goodrich's manufacturer warranty. The shop I bought them at said they'd give me 25% off. How come the warranty doesn't replace them 100%? I'd rather do that than buy a single tire.

How bad is it to have Falken's up front and BFG in the rear (or should I put the newest tread in the rear?)