Easy Peazy--45 minutes to remove and replace.
MB Pro battery life had significantly declined. Battery status indicated "Service"
After buying the iFixit kit I began to doubt there was an adequate spudger tool, so I got back on line and ordered a spudger tool pack for an addtion $6 plus shipping. Everything arrived together 3 days later. I performed the operation on my kitchen counter. Lots of extras in the iFixit kit that I set aside, but I was please to have an extra spudger. After removing the back, I disconnected the battery, removed the remaining two screws, and peeled back the tape. Then I slowly worked the the spudger tools under battery working left to right and right to left until all four outside cells were completely free. It was nice to have an extra spudger--it speeded the process by providing extra prying power. The center battery slides up and out -- no adhesive. I used some Qtips to dab the cleaner solution on the residual adhesive. Within a few minutes I had everything tidied up. The replacement battery fits in easily and no issues on startup once the case was fastened together.
An extra spudger tool is nice to have.