Even the F100-PW-100s could exceed the airframe's limits. The engines would be junk after a dash above 2.5, but if needed the extra power/speed is there.
Most sources will say the Eagle's top speed is "MACH 2.5+" and I'll add that the "plus" does indeed mean something.
(Even if it does break the aircraft and engines.)
Like posted before the "rated maximum speed" is quite often the accepted "safe maximum speed" for the machine as a whole. So yes an Eagle can fly around, fuel load/configuration/altitude permitting, at MACH 2.5 without a problem. When you get into the "2.5+" category, many hours of maintenance will be required after flight, and 2 new engines will most likely be needed.
Hey VarkVet, didn't the Vark get above it's "MAX Speed" back when... Without giving numbers, I've heard stories about it's dash performance too. Impressive for the TF-30s!
Keep 'em flyin'
TEG
Oh; remember the Raptor's Max Speed is only "MACH 2 Class" 