Replacing the rear suspension with a tubular kit from CPP. I notice the upper arms are turnbuckles that allow adjustment. The stock arms of course do not.

So my question is; What is the purpose of this adjustment range? Is it just for fit alone or can I control something else like ride height? I'm picturing that if I pull them in, making them shorter, the ride height should drop and vice-versa. Am I correct or is the adjust feature for fit purposes only? Thanks!

Mainly for adjusting pinion angle when altering ride height. The OEM units offer NO adjustment, as you can imagine as they are stamped steel. ;)