Not sure what you mean by loose.Does the car make a noise when you go over a speed bump?
These are the guys to use with any fox-body suspension part. Subframe connectors will help to stiffen the car, a strut tower brace will help too.Maximum has a really nice strut tower brace that uses the pinch welds allong the firewall instead of drilling through the firewall like most designs.
Maximum Motorsports :: The Leader In Mustang Performance Suspension