Hello
I'm in the same situation.
I bought my mbp in septembre 2012. After fews months i had to return the computer because the hard disk was bugged.
At the Apple Store Louvre (paris/ France) they constated the dysfunction and replaced free the hard disk a one month ago. BUT the new hard disk was noisy in the lower right corner. So I returned to the apple store one week later and they said me that the noise it's because 3 times I used time machine before with anothers olders macbooks. so they gave me a process for backup "clean". I made it 2 times and the HD made ever the same noise !
I phoned them, they said me to return a another time, I returned the computer last saturday, they changed the HD a new times and yesterday evenning after test at home, I have exactly the same noise !!
Today, I return to the apple store and they said it 's normal noise ....
I am very disapointed, I like Apple and i 've many apple's products but people at the genius bar in Apple store Louvre paris laght at me.
Do you have any idea for after, i don't know what to do now ?