replacing the 3.5” hard-drive with a 2.5” ssd - needed to use a 2.5 to 3.5 chassis and discovered that the existing sata cables are too short (in particular the sata data cable). purchased an 8” extension ($7) and squirreled the excess behind the chassis. worked fine.

i used a very sharp dental pick - a tool i've permanently "added" to my ifixit tool kit bag

When reassembling be sure not to bury any of the various connector wires under the logic board.