I ended up doing this last year. I bought a Sintech adapter and a Toshiba XG4 SSD for my 2015 15” rMBP. It works just fine but the battery life ended up being t

I ended up doing this last year. I bought a Sintech adapter and a Toshiba XG4 SSD for my 2015 15” rMBP. It works just fine but the battery life ended up being terrible compared to the stock SSD. I was getting around 60% of the battery life of the stock SSD with the XG4 + adapter combo.