Replacing the mirror is a trivial fix as even I did it twice successfully. You can do it.
The opportunity is to consider if you want to replace with the simple flat mirror or an aspherical one that allows you to cover your blind spot at the cost of some symmetry in the display. I went asph in both my Boxsters. A Porsche part.
If you want flat, ask one of the guys that is parting out a car rather than paying list. Any mirror from a 986/996 will fit. When I totaled my '99, it was one of the upgrade parts I pulled before the insurance company bought the carcass and I installed the asym into the '01S
The mirror you just pry off. Rotate with the switches till you can get your hand behind the edge and pull. Or just gently press it at the far edge until the near edge is accessible. There is a heating wire connected to the back and it is obvious how to disconnect it. The Mirror itself is mounted to a circular part in the mirror assembly and is just a firm push to install.