True but are they as big? Haven't done much research on this, plus I found some nice rims that are 5 lugs but I can always try to find them in 4.
It depends on what diameter rims you want to run. I made my own 4 lug, 4 wheel disc brake system based on modified rotors from a Lincoln LS, 11.8" front, 11.33" rear and calipers from a 2000-2002 Lincoln LS. They do require 16" wheels though.
2000-02 Lincoln LS rear calipers and pads are VERY similar to 94-04 Cobra rears and can use Mustang e brake cables.
If you wanted to keep 15's I would use re-drilled 94 T-bird rotors (10.16" vented rear and 10.85" front - same front size as SN's) and re-drilled hub from '89-90 T-bird along with '94/95 or 96-04 spindles (I am using the later).
If going 4 lug with SN95 spindles, use the 89-90 T-Bird hubs with the smooth back as shown. This way you can re-drill easily for different bolt pattern.
I used T-bird/Lincoln rotors and hubs because they are 5x108 - same bolt circle as Fox 4 lug. This way you can use one of the original studs/holes for alignment purposes to drill the other 3.
My re-drilled rotors.
11.8" rotor with dual piston LS calipers on 16", 11.33" rotor with LS rear caliper again in 16"