If you have a RWD vehicle you might save some MPG by converting to a 3 or 4 piece drive line.
Was helping a buddy on a Salt Flat car and noticed he had a 7 piece drive line.
He said they found the drive line can cost you over 15 HP as you approach a hundred. They found that several differing length pieces stop harmonics in the drive line and it runs smoother. You just have to build the carrier bearing holder for them...
Always wondered why my BMW had a 2 piece drive line.... When it doesn't have to flex..
Dave..