Unless you wrote your own new software for the player, the extra RAM wouldn't do you any good. Any existing software would not take advantage of any extra RAM you installed.

So if you needed to do a custom software project that required the extra RAM, then it would be useful. But the amount of difficulty involved in installing extra RAM into the car player is significant. It's not something just anyone can do. It doesn't plug in, it's all SMT and very delicate.

Just trying to upgrade the RAM without having a specific need for it wouldn't be an efficient use of your time.

Did you have some specific piece of software you wanted to write which needed the RAM? What did you have in mind?