Popular four link conversions

Hey Guys. I’m looking for some opinions on popular four link systems. I’m a fabricator in Michigan and I was looking to go into production for A body parts. I have a 68 dart myself that will be used as the mule. For the back I’ve seen a few kits out there that are nice but are missing the mark on some areas for more of high horse power applications. I’m planning on a kit that is easy to assemble and you only need a few tools to install. Upper and lower torque box (parallel style) not triangulated. Panhard bar, coilovers and rear sway bar. Street and Drag friendly!
What are some things that you’d like to see this kit have? More clearance for exhaust? Least amount of cutting on chassis? Strengthen areas of some other kits? Lastly are these conversions popular?