I have a x-link on my SG roadster. I don't see why you couldn't do it on a door car. I'm pretty sure it's used on dragsters and narrow cars like mine because of the limited space for a track locator or wishbone. It is more difficult to move the lower bars, and moving the rear side to side to center it in the car is challenging too. I'd think any chassis shop could make one or convert you current lower bars to x-link configuration.....
Johnny