Originally Posted by Tony@AirRideTech
keep in mind welding that a factory C4 crossmember to your frame is about like welding a tin can to an anvil. The C4 stuff is good stuff don't get me wrong but I would look at getting with Bob over at Progressive and talk to him about one of his crossmember to convert it over using your C4 stuff. Then you don't have to re-engineer anything and the rack, proper ackerman, track width is already figured out for you.
Welding a tin can to an anvil? Really? Have you ever installed one?
As to the geometry, that is the beauty of the C4 suspension, the whole factory crossmember is utilized so there is no
alteration of the factory geometry. Ackerman isn't enough of an issue to alter steering arms that can compromise other issues. A few hours of cleanup on the factory crossmember removing motor mounts, external mounting flanges, etc and you are good to go. You will have to build upper shock mounts though. But that isn't difficult.
If you have the cash, buy the kit. If you have the time but not the cash (or want to spend it on something more beneficial like really good tires) use the factory crossmember.