Hi everyone,
Time for me to chime in here, since I am responsible for this suspension. I had designed this for my CMC Cobra and managed to convince Tony to do this on his as well. The advantage of starting with his is that it's much easier with the body removeable (mine is built already).
Basically, the problem with the stock suspension is that it is the same hacked design that comes from the Fox-body Mustang -- you'll notice that Ford angled the upper arms *significantly* to prevent side-to-side motion of the axle. This saved them the cost of a panhard or other lateral locating device, but it binds bigtime! So to compensate, they made the bushings huge! IE: sloppy!
On a Cobra, this poor suspension is made even worse by the inability to appropriately position the forward mount-point of the lower control arms in the stock (Mustang) location, so they are lower. Now the geometry is all messed up. I've seen this with my CMC and many other Cobras. However, I think Factory Five figured out this problem and compensated for it somewhat with some add-on brackets that lower the rear axle position. Still not a complete fix though.
The new suspension is a regular 4-link design, with parallel arms (the proper way) and a panhard as the lateral locator. However, the geometry is much different -- I calculated the geometry to eliminate squat and brake dive as much as possible, and with the adjustments provided, it should be able to provide more than 100% anti-squat (ie: the rear *lifts* on hard acceleration to press the tires into the road surface). Of course there is a compromise point for regular road driving, which is best determined by testing road & experimentation. This new design also eliminates the horizontal quad-shocks which were necessary to eliminate wheel-hop (due to the sloppy bushings). If necessary (which I doubt), I may steal a nifty idea from the bowtie folks and move one of the shock mounts to the forward side of the axle. I also chose rod-ends with a small high-durometer rubber bushing rather then sperical rod ends since it's street driven and needs some vibration isolation. The panhard is actually horizontal -- perhaps you're confusing the diagonal support bracket for the panhard?
BTW, I did consider a Watts link, but with the ability to get a long panhard arm in this chassis (difficult with tubbed vehicles), the Watts is not necessary.
Only thing missing at this point is a good sway bar.
And of course everything is adjustable and on-the-car-adjustable in most places (using LH and RH threads) -- all three roll axes (yaw, pitch, roll), all three translation axes (lateral, longitudinal, height), and other things like specific angles of upper and lower arms, panhard angle, etc.
Only problem is that now I have to do this on my car too, but will have to remove a bunch of things like the fuel system and lines since there will be some torch cutting and grinding necessary.
Cheers,
-Neil.