The front and rear suspensions of the '98 to '12 Crown Vics would be a nice upgrade, and the front suspension has become popular for retrofitting to older cars and pickups.
The problem, the Crown Vic is wider, with a 63.4 inch front track width, compared to 61.5 inches for our cars. The rear track width is 65.3 inches, compared to 61.0 inches for our Mustangs.
You can't compensate the wider track width of the Crown Vics by going to a wheel with more backspacing (positive offset) because the Crown Vics already have a wheel that is basically flat faced with a lot of positive offset. This would require a custom, narrowed front suspension. The Crown Vic rear axle would also require narrowing, plus a lot of chassis work, as it is a 4-link Watt's linkage rear end.
You can buy all of the parts needed from a 71-73 donor car for the front discs, buy a complete upgrade kit for the front and/or rear brakes, or buy a conversion kit from
Mustang Steve that are for retrofitting newer Mustang front or rear disk brakes.