Hi Eleni,
We have a 280EC with the D4 260 engine.
We are completely satisfied about this engine in combination with the boat.
Cruising speed around 48 kmph at 3000 rpm's and fuel consumption than around 33 - 35 litres per hour.
Max speed 63 kmph with fuel consumption than at 52 litres per hour.
Slow speed (10 - 12 kmph at 1000 rpm's) with consumption of only 2 litres per hour.
In general, over the year we make between 150 - 200 hours (now 4 seasons with 600 hours total) and an average consumption of 7 - 8 litres per hour! (and we use cruising speed and also WOT at least once a day as our favorite area is 25 km from our harbour).
Also the sound is very good, for sure not noisy.
Mostly we are with 2 - 4 persons at the boat, but even with 6 adults and 2 kids we have no problem to come into plane (only than we need to trim the engine completely in and the plates completely out for the first few metres).
Love your area, we dream about the Greek waters (especially 2011 was in Holland terrible summer, spring and autumn Ok but summer wet, cold, dark, so only few hours

).
Keep us informed.
Hans