The F22 is quite capable of flying A LOT faster than it's stated max speed after all it has pleanty of thrust to reach M2.0 and faster (probably at least as fast as an F15). It was decided at the design stage to set the top speed at M1.7 because the F15 in service didn't oftern reach it's max speed of M2.5. To have the F22 reach such speeds the leading edges of the wings, intakes and stabs etc would need to be lined with titanium. Several other small mods would be required so if needed it can be done. Why nobody told this to the politicians is beyond me. If I was the head of the USAF I'd modify one Raptor in this fashion and take back the time to height records from the Russians.