Still got vibrations

[Cloggy Saint]

I've posted about this before but didn't really get anywhere, time for another shot. Basically my M20 touring has a fine vibration that I feel through the floor pan/pedals when I accelerate between 2000 and 3000 rpm. As well as the vibration the engine note seems to change from the usual smooth purr to more of a harsh growl. It's also the same if I take my foot off the gas in this rev range. Any ideas anyone?

[HairyScreech]

exhaust? i know my after market standard one causes the floor pan to vibrate a little at this rev range, noticed it shortly after i fitted it.

[Cloggy Saint]

I thought it could be exhaust related but it´s been checked out and is in order. It´s been fitted for a good few years now anyway. Could a broken manifold stud cause a vibration that could be felt through the floor?