I dont think hes asking about anything modified since that arguement usually goes no where being that for the right amount of money and the proper know how anything can be made to go fast or faster.
I like to stick with any stock car, straight from the factory for comparison's. That being said, I think the current GT500 is the fastest one.
1995 Mustang GT 5.0
BBK CAI, Pro-M 75mm MAF, Pro-M Optimizer, BBK 70mm TB, GT-40 Intake, 24# Injectors, AFR 165's, 1.7 Roller rockers, Crane 2040 cam (E-303) BBK Equal Length headers, BBK O/R X-pipe, Flowmaster American Thunder 2 Chambers. FMS 3.73 Gears, Lentech AODE 2800 stall, BBK 255lph Fuel Pump, BBK Fuel Pressure Regulator. MSD 6AL, Steeda UDP's, FMS Aluminum drive shaft, Autologic chip Larocca tune.