I wanted my next Notebook to be a Macbook Pro 13" with the highest specs available. But it comes with 8GB only, the 15" has soldered 16GB RAM and a soldered 750

I wanted my next Notebook to be a Macbook Pro 13" with the highest specs available. But it comes with 8GB only, the 15" has soldered 16GB RAM and a soldered 750GB SSD. These were the reasons I cannot buy it. I wanted 32GB RAM or more, it's soo cheap! And I want the option to replace my HDD with a faster one.