I just replaced the factory speakers and stereo yesterday!
I did find it a little challenging, but I'm not a really skilled person for this kind of stuff. Basically I just found tutorials and followed them to the best of my ability.
Both front and back speakers require removing interior panels which can be a little intimidating. Based on the videos I saw, it seemed like the rear 6 x 9 speakers would be the most difficult. The only problem with that was misaligned holes. The original holes did not match the new speakers and I had to drill new ones.
The front speakers required removing the entire inside door panel. Once removed, it became obvious that the 6.5 speakers I had purchased would not fit properly because the factory speakers were mounted in a custom component type thing. You have to drill through rivets to remove them and once off, I had to fabricate my own adapter/brackets out of a steel sheet. I also had to drill some new holes.
If I could go back (and like I said I'm sort of a noob at these types of things) I would have either bought component speakers or some speaker adapter/brackets to make the fitting go a little smoother.
The stereo was not that bad, but it is a little nerve racking removing the center console. You have to pull and it feels like it will not come off without breaking. I ordered this
and it worked well.
Sorry this wasn't really a suggestion for an audio system. We went with a kenwood head unit and speakers and it was a BIG improvement over the factory system in volume and quality.
I'm sure I made the install sound more difficult than it actually was, but I'm not really a "car" guy and I don't have a big arsenal of tools. This is more of a encouraging post...If I did it, you should have no problem! haha