I did mine in a day and at best taking my time I was able to get through it in about 5 hours. Just a note on going with glass if you have an earlier model Box the glass can limit your ability to access your engine as comfortably as you can with a soft top.
Now with that said, there are a couple of parts you want to order before you start your project. You will want to have these in place:
left slide 986.561.669.03
right slide 986.560.670.03
right clamping piece 986.561.559.01
left clamping piece 986.561.560.01
pins 986.561.597.00 (get 2)
Note: I found that I was able to salvage most of my older tops parts which fit better in the new top than the replacement parts...but that was me. You will break a pin, so while it suggests 2 get 4 their cheap. Here is a really good how to thread from Pelican. I used this along with Mike's webpage instructions. End result is I have a perfectly tight top.
This is the site you really want to study:
https://sites.google.com/site/mikefocke2/replacingthetop-adiy
Here is his main page:
https://sites.google.com/site/mikefocke2/mikesporscheboxsterwebpages
Here is Pelican's
Pelican Technical Article: Boxster Convertible New Top - 986 / 987
Good luck!