The P-51 is a wonderful plane to fly with an excellent example provided by A2A.
However those in FSX are fairly benign.
If you really want a feel for how difficult it might have been, try the free civilian P-51 in DCS World. It was a few weeks before I could get this off the ground reliably and I had to research the take off problems that pilots had in the 2nd world war to find out why. The problem is that if you trim nose up for take off that will keep the tail down on the ground and in that attitude the plane will lift off the ground before it has enough aileron authority to stop it flipping over because of the torque. You absolutely have to get the tail up and let it pick up more speed before allowing it to lift off. Also be aware that there is a Special setting for the P-51 that provides take-off assistance set to 100% as the default, so you obviously want to set that to zero. You can install DCS and try out the civilian P-51 completely free of charge and it is a wonderful plane to fly. Reliable take-offs and landings are extremely satisfying. Also the P-51 is very sensitive to rudder trim and will behave in all sorts of unexpected ways when out of trim.
Silver
Works fine for me and is a decent model so it is probably the way you have installed it or perhaps you don't undertand how to operate turboprops. Its often instructive to watch the CTRL E startup actions and copy them for manual starts. If something doesn't work right the best starting point is always to try to work out what you have done wrong and eliminate those possibilities before criticising other people who generously share their efforts with us. Many thanks for your generous efforts Paul.