I used Kevlar on a few installations and though it doesn't stretch, attaching the end fittings seemed to to be a pain at times. These days I just use wire cable from either hobby sources or fishing tackle suppliers. The cable seems much more tolerant overall than Kevlar. You can get anything you want from the large fishing tackle suppliers including bare steel cables in several different alloys, coated steel cables on through Kevlar and other composites. They also have the sleeves, crimp tools and most anything you'd need for a control cable in a variety of strengths and sizes. Much cheaper than hobby sources!