If you have a burning desire for floats and are worried about corrosion, a Jabiru would be a perfect candidate for them. Not certified, but ok as an amateur built. Have been calculating recently, around $97k for a 6 cylinder J170 fly away and about $110k for a J430 on floats if you want 3.5 seats which is more than your 140 will ever fit! Either model should cruise at around 100 knots on 25-26 litres per hour with 5 hours capacity.