Last Saturday I took my car to a quick lube joint to get a quick oilchange. The "Mr's" at this "Lube" location reccomended that my serpentine belt be replaced. Having my young son in the car, I caved due to guilt.
I won't get into the details, but they put the belt for a matrix on my car because "They are basically the same car". Then they apparently put the correct belt on, but now the belt squeals like that scene from Deliverance.
To the fast lube's credit, they are replacing the belt with a belt from the dealer that I requested, and they contacted me within 24 hours of me sending them a nasty email.
Long story short, take your car to a mechanic for certain things. Avoid the fast lube places.