Build Question

I have a 20" Upper and just picked up a stripped lower for this build. Question is do I need an A2 buffer, tube, stock and spring for it to function properly or can I use a collapsible 6 position stock and buffer assembly? I have been told both ways and want to make sure I get the right parts. Thanks in advance.

Barrel length is of minimal consequence unless it is a radical change say in the case of a pistol.
If you are running a CAR stock be sure to use the CAR spring and CAR LENGTH buffer. Buffer weight shouldn't cause too much of an issue.
Where you will run into trouble is if you start trying to mix n match bits and pieces. A rifle buffer and spring are longer than a CAR set so for example if you try the rifle buffer in a CAR you are going to have issues.

Thanks for the reply! Just want to make sure I do it right.