Re A109E - note that there is now a mod for increasing the MAUM which ought to give some range when full IFR flight prevails.
Sensibly, the passenger load in a 109 would be 5 pax and pilot for an IFR flight with more or less 860 litres of fuel and the u/c mod the range and reserves should be as good as any other twin in IFR configuration.
I notice that nobody has mentioned the MD902 - why?