I’ve had a 2.7 Boxster for a couple of years now and love it. It isn’t my main car but I do use it for trips away with the bike on the back. Tax, insurance, servicing and fuel consumption aren’t excessive. Yes, repair bills can be pricey but they can be with any car and hopefully few will be needed.
If you really fancy a Porsche – go for it. If you just want a little convertible there’ll probably but more sensible choices.