The beauty of the Boxster, mine being a 2001 Boxster base is that I am not concerned where I park it, if it is stolen etc because I don't have many $$$ tied up in it. (That is what insurance is for ).If I had a newer 996 then I would be more paranoid about it. The Boxsters 2nd hand are pretty cheap to buy, if the engine blows up it is not the end of the world -for me anyway. If it happens it happens.
If you have a Box and 996 you definitely have the best of both worlds. Two different kinds of car and each have their own unique benefits. But then you need a bigger garage presumably if your GF has a car too.Anyway good choice guys!