Quoted from 3ZC
"I originally purchased the adjustable tension rods and upper arms from Courtesy parts. The upper arms seemed ok, but I was not happy with the quality of workmanship on the tension rods. I returned the whole setup and purchased everything from SPL. The quality of the SPL merchandise seemed far superior to that of what Courtesy had to offer. The ones from specialty z appear pretty similar the ones from Courtesy."
And I heard the same from some others, I am now looking at Specialty-Z.