im tlaking about customizing the computer before buying it LOL
Huh?
I thought that with cMBP, you could purchase a base model and upgrade memory and storage at a later point which is generally cheaper. But with rMBP, once you purchase the system, you could not upgrade either memory or storage later.
If you buy a system with 8gb memory and 512gb storage, you can't ever increase it with aftermarket parts.
I'm waiting to get my first MacBook, so all this is new to me. Correct me if I made the wrong assumption.