All of those points you raised about the F-14 are true to life. Long negative G runs were actually prohibited by the USAF. http://foxtrotalpha.jalopnik.com/the-five-maneuver..., the F-14 was a big plane and not necessarily the most agile, but I think it was still more agile than a MiG 31. To my knowledge the only production jets faster than a MiG31 were a MiG25 in afterburner and an SR-71. The only other faster jets tended to be the experimental ones. And as for the MiG25, getting it that fast tended to involve wrecking the engines in the process.