I've flown -200 and -400 Civil Types, and as far as Feild legnth/payload goes it is pretty good. The -200 would go in to 570m at 4000' at 7700kg no problems but could only carry about 500kg out (BEW around 4800). The military operate them to 8100 MTOW and with both engines running this weight isn't a problem. Even at 35c. (you get about 80% Torque, 650 EGT)
The -400s are pretty new and have 25hp more per side but are a couple of hundred kgs heavier and seem to perform about the same. in ISA -15 temps they have been known to operate at 8470kg. More in Ferry situations.
if you have any more Q's, i'll be happy to try and answer
Ya