I’ve installed the Hotchkis subframe connectors on my Challenger, install was straightforward and the welding was pretty simple. I also like how on the E-body the Hotchkis subframes back up and strengthen the rear spring mounts. Tying in the suspension mounts directly is a nice touch. And all the lines can be routed over the top, no big headaches there although some minor re-routing is necessary.
I’ve also made my own connectors for my Duster, and used the US Cartool connectors on my Dart. I can tell you that the only way I’d install the US Cartool subframe connectors again is on a car that’s been media-blasted and put on a rotisserie. Welding those things in upside down, even after wire wheeling the whole mounting area, was a pain in the butt. I’ve used all their other chassis reinforcements, the lower radiator support, forward braces and torque boxes. Those all fit well and were fairly straightforward to install. But those subframes were a lot of work. And then you have to re-route or tunnel the lines through.