I did a search but have not seen anything close to my problem. When my car reaches about 3000 RPMs the shifter starts vibrating really bad, at about 4500 RPMs it goes away. It is a T-5 and it vibrates in any gear, does not vibrate in neutral, and stops as soon as you put depress the clutch.
rowdie, I have a similar problem with the vibrations/shudder transmitting through the shifter (see my thread --> http://forums.stangnet.com/showthread.php?t=670133) but at 70mph and above. I checked my U-Joints and they seemed to have noticable play in them. You should check your U-joints as well. So I just last night replaced my u-joints with new ones and will test drive tonight. Ill post to my original thread with the results.