Switching from PCI-e Flash storage to SSD
I am looking into purchasing a Macbook 2015 15''. I am very particular with the specs and price range and I want to know if there is anyway to get a macbook with PCI-E storage and in the future, upgrade it to SSD? I see many questions and answers on upgrading the storage but not changing it completely from PCI-E to SSD. If so, how hard, expensive is it to do?
Thank you!
Is this a good question?