Start with 1 2.5L version, cheapest initial investment & starter Box for you & customers also.
You will learn what will be your next move.
IF everything goes perfectly your biggest expense will be tires & brake parts which are considerably cheaper for the 2.5L Box. Only plus for the 3.2 Box is stability control & more speed/power.
My wife is Greek & we are way past due for a trip there, I am a Boxster mechanic/engine builder, maybe we can help each other!