Aligned post install. I feel like alignment or wheel issues would create vibration at certain speeds, axle issues would create vibration only under load like hard acceleration which is what im feeling. I had a mustang once with the same issue on a stock suspension and the dealer found it to be loose bolts on the drive shaft. This feels very similar . I could be going 60, 70, 80 etc without giving gas and there is no vibration. Its only under moderated to heavy gas pedal pressure