My Hard Drive crashed, so I decided to replace it with a 1TB WD from OWC and double the memory from 4GB to 8GB also from OWC
This was my first time replacing the Hard Drive and Memory. I had absolutely no problems. The tutorials on youtube and from OWC were straight forward and easy to follow.
You do not need to remove the battery. Everything will still work if you replace/upgrade while the battery is still hooked up. It does not matter in the newer macbook pros, unlike the older macbooks. The Anti-Static Wrist Bracelet is not necessary, but for a few bucks is a great security if you do not have a designated static free work surface. If you are wondering, where to by and from who, OWC has package deals and the products are genuine. I would recommend them.