Driveshaft shortening

One major advantage to having something like this done by a shop is "Warranty and liability" and not hoping that the job was done correctly. Not everyone is a capable welder or has much fabricating experience, telling someone that it is easy is easy. Seldom is doing something that you have never done before easy the first time. There is always a learning curve and everybody's is different.
The flip side of saying " I did it " is "it was my own fault"