The 2003 and 2004 Cobra code name "TERMINATOR" was Ford's chance to put the Mustang back on the map. Up until this point the mustang simply couldn't compete with GM's 5.7L F-body's. The answer was a 390 hp 4.6L 4 valve supercharged cobra equipped with a 6 speed T56 and an independant rear suspension. Although plenty of strength was given to the terminator from the factory they left plenty of room for upgrades. A simple swap of supercharger pulleys, cold air intake and performance tuning and an additonal 100+rwhp can be acheived. At that point a performance clutch, shifter and other suspension modifications become very helpful. Then there's the ability to slap an aftermarket supercharger on such as the 2.3L or 3.4L Whipple and gains of over 200rwhp can be acheived. When you reach that point you've definitely reached the maximum efficiency of the stock fuel system so larger injectors and multi pump return and returnless fuel systems are available to help safely support the power.