Okay, I had enough of the factory craptastic paper cone speakers.
I just wanted something better for now. So I bought some cheap JVC 3-way 6x9's and 2-way 6.5's. They're 45w and 30w respectively with a high sensitivity rating of 92db. The magnets on the 6x9's are almost the same as factory and the 6.5's are slightly larger.
I made sure to fix any gaps between the speakers and mounts, mounts and door panels. So I used 1/4" wide by 1/16" thick adhesive foam. This way I could seal between the door and mount. And the mount and speaker. As well, on the 6.5's I used some on the other mounting holes that weren't used, these would have caused air movement noise and would have sounded like ish!
So, before and after?!
Before, half volume and the bass would plateau. It didn't really punch or pop, and sounded pretty generic like a boom box.
After, highs are clear, and mid range/mid bass are definitely better. The bass climbs, as well the overall volume level, as the volume is increased. So the "myth" that the bass is throttled via amp, is incorrect!
I did buy the cheapest speakers available at this time, and they're a few notches over the factory speakers. I'll probably get something slightly better in time, and need to find a way to seal better the speaker and door panel cover, so I'm not losing any sound inside the door.
Also, I had to fix the holes in the passenger side door grill, the moulding process left a lot of material behind.
TLDR; yes, factory low end stereo with better speakers was a good upgrade and about 3x better sounding than factory paper cone speakers.