It's a simple "snap-off" old and install new. Idiot proof, can't go wrong with the installation.
It's designed to increase the vision whilst also providing the Euro blue mirrors found commonly on BMWs, Mercs, VWs, Audis, etc. If your windows are already tinted, I wouldn't suggest this, it'll further reduce visibility particularly at night. However if your windows are not tinted, this will be a worthy upgrade if you find the OEM mirrors "insufficient".
I never thought side mirrors are a solution to a larger cabin/interior rear view mirror. The side mirrors are used to see traffic and park. While the larger cabin/interior one is used to see traffic and cover blind spots if it's big enough.