Installing new SSD in late 2011 MBP

I am looking to install a Crucial BX300 SSD in my Late 2011 MacBook Pro 13"

1) I'm choosing between the older 525 GB model and the new 480 GB, specs are:

• Old model: 525GB 2.5-inch internal SSD • SATA 6.0Gb/s • 530 MB/s Read, 510 MB/s Write
• New model: 480GB SATA 6Gbps 2.5" Internal SSD • 555MB/s Read, 510MB/s Write

Is there any material difference other than the size?

2) What is the best method to back up the Mac before I install the new drive?

I use Time Machine and also have various portable hard drives.

3) Does installing more RAM make any difference, or will the SSD be sufficient to see significant improvement?

The current memory is 4 GB (1333 MHz DDR3) and I believe it can be increased to 16GB

Thank you