Thank you guys for your feedback.
The reason behind the TC engine is because the circuit are done at 10 000ft, in ISA+10 to ISA+20 conditions so we need the extra performance.
Twin engine is best due the montainous environment and it allows us to have no pre defined circuit hence we can adjust the flight to the meteo.
I know the P68 can get very hot in the cockpit so the A/C is a must have.
Thank for the advice regarding marine air, I think too that A/C in the hangar is needed to reduce humidity and corrosion.