A couple things first... How much money do you want to spend and how much can you afford?? Cash outright? Monthly pymnts.?
Making $25k/yr. is great as an undergrad... unless you spend $26k
Boxsters are expensive to keep, even though their purchase prices are temptingly low.
928s are fairly cheap, the car is reliable... but parts are still $$$.
944s are cheap, fairly reliable but difficult to find nice ones not needing parts - also $$$.
914s are creeping up in price, esp. good examples. Less complex and parts are less expensive, maybe only $$.
How are you going to use it? How long do you plan to keep it? How 'perfect' do you want it and/or are willing to make it? All these things will effect your decision.
Reflect on these things and the current (and maybe future) economy. Given your situation, is a reliable Toyota or Honda a better choice right now? Starting a 'car fund' to give you a nice 'graduation present' once you are finished school and have a good outlook at your future? I'm not saying... these are things only you can decide.