I never did understand why low level nav at 300KIAS was approved for the JP. At 240KIAS the aircraft flew very nicely, but at 300KIAS it bounced around like a pea on a drum and needed full power in any signifcant turn to maintain the speed. Also the standard timing correction technique for late ETA really caned the aircraft and its engine. 10 sec late at 300KIAS meant increasing to 310KIAS for 5 minutes; anything more could easily exceed max. continuous rpm....
OK, 300KIAS was more fun as was a 300KIAS / 300ft agl VRIAB. Quite how the little Viper stood up to such abuse I don't know - but it certainly did.