Base model radio upgrade question

Inspector71

I have a 2015 base. It appears there are two speakers, one in each door, and that is it. There are what appear to be speaker covers at each corner of the dash. Am I correct? If I upgrade to a better Nissan radio, will I be able to have speakers put there? I am not interested in nav and all that, just a better sounding radio and speakers. Thanks.

After some more research I see how much has been written about this. Stereos/speakers, and much of what I read is over my head. I am a low tech guy and I don't want to waste anyone's time. I guess what I'm trying to ask is, staying with Nissan, can I upgrade through them to a better radio and would I be able to get speakers put under the covers in the dash? Any idea what this might cost? As to after market stuff, I realize it may be way better but I'd have no idea what I'm doing. If it involves wires, I'm probably banned from touching them.