First off buy a used one. You can save quite a bit of money buying used. Try using CarGurus DealFinder to find the best deal in your area
http://www.cargurus.com/Cars/l-Used-Porsche-911-d404
Unless you intend to drive the car in the winter (ie need 4 wheel drive), don't bother with the 4 or 4s. The carrera S is an amazing car and quite a bit cheaper than the 4s. One thing to consider is the PDK electronic clutch. While a manual is so much fun, the PDK gives you all the performance of a manual but no need for the clutch pedal. In stop and go traffic the PDK is so much easier. To be clear the PDK is NOT an automatic transmission, it is a manual but the clutch is electronic - similar to Formula One cars.
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