Part of the issue with emergencies in expensive Warbirds is that there could be a temptation to try and save the aircraft till the bitter end. Consider Gliders on cross country flying. They regularly make safe off-site landings for several reasons. Their landing speed is lower but, they always make a glide approach anyway so their handling skills are practiced. They generally have well considered plans for setting-up and executing a "forced landing", so they use the plan and land safely. I have never seen a Mustang make or practice a glide approach. The usual is a powered approach with a high RPM for engine response. This is the best way to operate them but, any serious loss of power may present the pilot with a scenario he is unable to deal with on approach. Generally, loss of power sufficient to continue normal flight in Piston warbirds would lead to a wheels-up forced landing in the original flying manual and, this is can the safest way if the pilot is trained for it.
OAP