[joyridin']

You probably need to do a search of the site and read what a few others have encountered. They had the same problem with the upper mounts and had to remove them and reweld.

The manual is worthless. It will tell you nothing.

The car was designed for a Mustang 2 rear axle. You can install basically any rear end from a Fox body without any issue. Does it have adjustable upper arms? Are they aftermarket or OEM stlye? As for the springs, they may just have the wrong style installed. They almost sound like they are too tall and stretching the limits of the control arms. The car was designed for small rear tires. You can put bigger on it, but if they are really tall, maybe the springs are tall for tire clearance?

Shock bushings are easy. Are they just standard shocks?