Well it will be cheaper for one thing but more complicated because you gotta fab just about everything, where as a kit everything is fabbed and ready to go on
This is correct. Depending on how you do it your gunna prob need to make headers, or get them made, run the pipe to the turbo welding on a flange.
You also have to tap the oil pan to have a return line for the turbo and also split the oil line for the oil inlet on the turbo.
You have to run all the cold pipes and make sure you get injectors and a BOV/BPV, and a few other things.
Now this is what I plan to do and it is WAY cheaper expecially if you get junkyard turbos but deffinately complicated and alot of work.
Worth it, I think so but its all up to what you want to tackle