ive done mine on my 2014 991.1 S -- took about an hour and a half to do - start to end.
I did buy a tool from amazon which was recommended in the DIY

Was easy and no need to remove the bumper - I did remove the rear wheels to help with access.

 

http://truedriverscar.com/docs/991_sparkPlugsChange

Found this DIY guide for the 991.1. Looks very detailed but not sure if similar to .2

 

I literally spent three weeks debating doing the plugs myself - looking under car, reading posts, service diagrams and finally settled on having the dealership do it for $650. I change my own oil, brakes, etc., but the 991.2 spark plug change did not seem as straight forward as the 991.1. There was just too much heat shield, turbo inlet, contortionist stuff to get around for me.

 

991.2 DIY: https://rennlist.com/forums/991/1233...intenance.html

 

If you change your own plugs, note that it is easier to reconnect them incorrectly. The coil pack wire is very flexible and unlike most normal plugs that are convex at the tip, the ones for the .2 are concave. You have to make sure you seat it properly or misfire gremlins will show up.

 

In the .2 we have turbo piping in the way, but it's otherwise quite similar.