Did some math...
So, I did some "research" about this topic. I think, it is a rpm-related problem - the faster you drive, the more rpm's you have on your driveshaft.
I assume we have some 235/50-18 tires on the Stang, with the conversion tool from 404page.html
that would be a circumference of (roughly) 85.6 inch. If we drive governed limited, that is 113mph - these are 7159680 inches an hour.
Divide the 7159680 inch through 85.6 inch (tire) these are 83641 rounds per hour. Assumed, that an hour has 60 minutes, this will be 1394 rpm on the tire.
Now we have different gears, multiplied with the gear ratio we have the rpm's on the driveshaft:
With 2.73 = 3805rpm
With 3.73 = 5199rpm
With 4.10 = 5715rpm
Now we can calculate with the (stupid!?) 135mph, as one example this will be 6212rpm with a 3.73 gear, which will have a lot of you (and me) guys.
So I think, here lies the rabbit in the pepper (German saying!)
I think we will need a well manufactured drive shaft which has really less tolerances and is well balanced. So, what promises give us all the driveshaft manufactures? Speed? That depends on our gears!
May be the manual trans has a little more vibration than the auto, but over 60% more rpm's have to be in mind.
Open for better suggestions, Turbofred