I replaced the hard drive because of the SMART Status told me the drive was going bad and to back up every thing you can.
I-Fixit made my job Soo easy with great Instructions, Both Printed as well as photos. When you buy the proper tool's the job and read the instruction's more than once or twice It's just is no BIG DEAL.
Yes I would recommend some double sided sticky Tape or rubber cement to hold down the sensor on the hard drive. Some towels from Harbor Freight worked fantastic for dust removal as well as canned air be carful of getting TOO CLOSE.
also a small paint brush to help dust.