I haven't done this repair on a Boxster myself (can you provide a photo of where you're at with the work so far?). However, from my prior experience under the car:
, this is probably like most cars (a tapered bearing which sits in a race within a carrier/housing), and then there are typically two ways to go:
1) remove the carrier/housing from the car and take it to a machine shop where they can press out the old bearing a press in the new. Usually a minimal charge.
2) Buy or rent a puller (at AutoZone or Taylor Rental, etc.) to pull the bearing with the housing still on the car. You then need a bearing drift (if I remember the name correctly - essentially a bar of steel with a set of stepped circular ridges at one end to fit into the center of the bearing) to drive it into the housing and seat it. Careful attention required or bearing damage can result.
(1) is less likely to cause damage but makes for more disassembly work - and may drive the need for the alignment after, (2) is faster but requires specialized tools and careful attention on your part.
This is a fairly generic answer but maybe someone else has done the actual job on this car before and can supply more specific info. Good luck!