A suggestion is to use something like this: http://janswebsites.altervista.org/flightsim/ai-aircraft-behaviour-v6acof.html
to make the AI aircraft slow down across a longer runway length.
Remember. Those FDE's are made for FS9. They might give different results in P3Dv4.
And also, the aircraft.cfg and sim-file might/will be changed back to the original one, when installing new paints for the model. And then it's not ideal to use them anymore.
as with the new added soundpack we haves till the idea of including improved FDEs