[Giller]

A lot of other factors go into the decision such as overall condition of the vehicle, maintenance records, previous owner.....as well as how you like to drive. The 2.7 has enough pep for me as I don't track it and everyday driving - well, if you keep to within a reasonable speed vs. speed you really aren't using all of the power of either engine.
I always say get as new a car as you can afford. Things wear down simply by getting older, so buying the older car will speed up the repair cycle. But - it's a Porsche. You won't be disappointed no matter which one you take.