I have a 2005 v6 manual 4.0l stang. Sometimes I notice when braking at fast speeds like 40mph+ that there is a mid-high pitch vibration throught the car, and i can feel it on my foot on the brake. It doesnt always do this, and I don't think my brakes are shot cuz i often use the gears to slow myself down and just break to ome to a full stop or lightly use them in combination with downshifting. There are 13,500 miles on the car now and its been doing this since my dad gave me the car at 11,000 miles. The car doesnt rattle, shake, niether does the steering wheel while braking.