Is there any way possible to downgrade iOS 7.0.3 to iOS 6.1.4/6.1.3? (iPhone 5)?

Just wondering. Is there any way to downgrade? ANY possible way?

Added (1). Would you recommend buying a used iOS 6 iPhone?

Sorry but there isn't unless you buy a second hand or new device loaded with ios 6

Nope. I've tried almost everything
I agree with @Oliver Clarke only way is to buy a device with OS6 loaded on it