From my '95 Mustang GT, which I just changed to IRS.
Stock axle, 2.73 gears, LSD, 28-spline shafts, disc brakes, 62k miles on it, 61 1/4 inches wide hub to hub. These 8.8s can cope with plenty of horsepower - have seen them run on many a 9 and 10-second car. Loads of aftermarket parts available for them and narrowing is commonplace, with shorter shafts available from most UK race shops.
Also have some brand new Ford Racing 3.73 gears for this axle, £75.