Congrats on your car and welcome to the forum!
The DIY projects you have chosen are very ambitious, they are the ones I have been hesitant to try but I prefer the electrical side of things, and have just started getting my feet wet on the mechanical side. However I don't think you should have any problems, the Boxster is very well designed which makes it easy to work on, and the most involved DIY you mention would be the spark plugs.
I would recommend shopping at Harbor Freight to get your tool kit started. Start with the basics, some screwdrivers, pliers, hammer, mallet, socket set, WD40, wrenches, etc. If you need some help do a google search for something like 'making a basic tool kit' and you should be able to learn what everything is and its purpose.
Once you have the basics then you can get into more Boxster specific tools. These are the tools I can remember having to go buy to be able to work on my car: allen wrenches (metric), a screwdriver with multiple bits (star, hex, etc.), and a torque wrench that goes to a 100 ft. lb. The only other tools specific to the DIY's you mention that I can think of would be an oil pan, and Porsche oil wrench.
Good luck, and I would recommend reading over the DIY guides, most of them mention the tools you will need.
EDIT: Also, if you want some information on your car try decoding your option sticker and you can also email your VIN number to Suncoast Porsche and they will decode it for you, look at the bottom of the page
here .