While the adjustable suspension solution for the rear doesn't replace the factory dampers with true coilovers, it does add coilover-like functionality by adding this billet adjuster to the stock spring perch on the axle. A tab securely mounts the adjuster to the perch. Once in place, it can be adjusted with a spanner wrench just like the front coilovers.
With it in place, Matt adds our new spring to complement the already-installed Tokico D-spec dampers. To deliver my wish for better handling with great ride quality, Steeda main man Dario Orlando specified 175-in-lb front springs and 200-in-lb rear springs; the results were beyond my expectations.
I wanted to leave behind the dreaded wheelhop the GT500s exhibit when you lay down big power with the stock suspension, so new control arms were in order. However, I didn't plan on spending a lot of time under the car tweaking its suspension setting. As such, I chose Steeda's trio of chrome-moly S197 control arms. In the case of the upper, Steeda offers one for stock ride heights and one for lower ride heights. Naturally, this shorter-than-stock unit is the latter one.
A direct replacement for the stock piece, the chrome-moly Steeda upper control arm comes complete with a bumpstop, but be sure to install the aluminum spacers between the bushing and the upper mount. While the three-piece bushing in the mount is said to reduce deflection while maintaining ride quality, you do give up a bit on NVH with all the suspension gear in the form of a bit more noise. There is a slight clip-clop sound coming from the suspension when the rear suspension unloads, but given that my stereo is at concert volume most of the time, I rarely notice.
With the car on a lift, the lower control arms are an easy swap. The only trick is to be sure and put the wider side of the axle bushing toward the center of the car as the arms are side-specific. Matt greased the bushings with a liberal dose of waterproof grease to ensure a squeak-free install. Keen readers will also target the Steeda lower control-arm relocation bracket Matt bolted into place first. Since PVT is going low, these brackets are a necessity to restore the suspension geometry and ensure good traction. Once everything is bolted up and adjusted, these brackets are welded into place for maximum strength.
Before busting out the welder, Matt added Steeda's three-point framerail and torque-box brace, which bolts in using factory holes. While S197s are far stiffer than their predecessors, a little insurance isn't a bad idea when your ride is packing 600 lb-ft of torque and rolling on Nitto drag radials. These chrome-moly braces triangulate the inner framerails, outer framerails, and torque boxes. After bolting on the two braces, Matt sparked up the welder and secured the lower control-arm relocation brackets and three-point braces.
On the home stretch, Matt checks PVT's ride height, dials in our new weed-whacking ride height, and ensures the measurements are equal on both sides. Lift the car with a jack or lift to unload the weight, which makes it easy to adjust the height. Once the ride height is where you want it, lock the perch in place with the Allen-head set screw.
With the up and down in order, it was time to upgrade the side-to-side. Steve and Matt teamed up to mount the Steeda Watt's link to PVT's rear axle. While a Panhard bar is a huge improvement over the prior Mustang's lack of lateral axle control, it does give up some precision. One end of the bar is mounted to the chassis and the other swings up and down with the axle. A Watt's uses two bars, which move independently and eliminate the lateral movement that the Panhard bar would allow.