From American Muscle.com Youtube Channel:
Light Weight. Lighter and stronger than the stock factory 2-piece driveshaft, weighing in between 18 lbs and 20 lbs, The Driveshaft Shop’s One Piece Mustang Driveshaft greatly reduces rotating mass to improve your Pony’s 1/4 mile track times.
Superior Quality. Constructed from 3.5″ diameter 6061-T6 aluminum tubing or 3.25″ diameter High Modulus Carbon fiber tubing. This driveshaft features a 1350 front u-joint with flange to mount directly to the transmission and a 28 spline 108mm 6-bolt rear CV joint made from an all new 300M material.
Extra Clearance. This light weight one piece aluminum driveshaft features a 3.5″ OR 3.25″ diameter design giving extra clearance needed to avoid interference that can happen on lowered Mustangs equipped with a 4″ shaft.
High Speed Balanced. Balanced on one of the most sophisticated balancing machines in the industry, at up to 9500RPM (revolutions per minute) this one piece driveshaft is rated for use up to 900 horsepower.
Application. This one piece carbon fiber OR aluminum driveshaft from The Driveshaft Shop is designed specifically for use on 2005 to 2010 GT and Bullitt Mustangs equipped with either a Manual or Automatic transmission.
The Carbon Fiber driveshaft clearly has advantages in weight, torsion / tensile strength and elasticity.