Yes I installed them myself. I reused the OEM speaker mount just like the OP, but instead of screwing the speaker to it, I used a thick bead of silicone adhesive because a: the mount is very thin plastic and b: the speaker is just a little too wide, Using the silicone fills this gap and acts like a very firm cushion for the speaker.
I would say these Morel Maximus are designed for sound quality not for outright volume, they are only rated at 60wrms. This means you could amplify them if you want them LOUD, but I've found a huge improvement in sound quality and more than acceptable volume.
The stock speakers were so bad, that I never enjoyed any music in the car. Until last week, when I went for a long drive by myself, I thought that the v8 soundtrack would be enough but sadly the novelty has worn off already.
I would recommend the Morel's if you are going to install yourself, as you can easily see whether they will be ok for you without any extra amplification, and then buy an amp and fit it afterwards.