Regardless of how much power you intend to build into your Mustang, you want handling that will keep you out of trouble. You want a Mustang that will hold the road. Install the fattest sway bar you can get under there in order to minimize body roll. Urethane bushings can be too stiff. One option is polyurethane, which is more flexible. One caution is strut rod bushings. Urethane bushings tend to break strut rods. Go with polyurethane or a fully-articulating strut rod assembly.