be sure you get the model with the posts on the correct side. (34R)
Also you'll need to make or buy a mounting plate kit.
And you may need a slightly longer grounding wire.
I did it and was done in 30 minutes of actual work. Never been inside a Boxster battery mount before. No special tools. I was about 65 at the time.
I ordered online with shipping included and it was cheaper than local purchase. I wrote up the procedure at
https://sites.google.com/site/mikefocke2/batteries
While you are in there, make sure your 2 front drains are clear.