I'm not sure what the Grand Viziers of Street Modified have to say about this lately. A while back the idea of the suspension rules seemed to be, "Unbolt any and everything from the car's frame, and bolt up whatever you want to pretty much where you want to - as long as it's into OEM holes in the chassis." So that would mean I should be able to custom build a dual A-arm front for my car and have it be legal as long as I'm not drilling & tapping new holes in the chassis or welding it on. But, some cars have entire suspension subframes that bolt up (like the Mustang's front end, in particular) to the unibody, and so far the Official Word From The Ivory Tower is that bolting up a new k-member to the frame like that is extremely not allowed. So, to (not) answer your question... who the hell knows. SCCA can suck it.
