Mustangs were available with the HO 5.0 in the notch. I owned a 1992. The suspension & drivetrain were the same as the GT, only the body and trim were different.
To run ITB you would have to use the smaller front brakes, drum brakes in the rear and the 7.5 rear. The Steeda rear suspensiion is not IT legal since you can't remove stock links, but you can add a panhard bar.