Solid axle would be a disadvantage, you'd probably want a cobra motor, blueprinted with some killer valvesprings, bull-nosed, knife-edged crank, the key is just to have tons of rev, because you need to stay mostly in one gear. I used to drift my 240SX, trust me, a Mustang is a little fat to be running that way, but if you insist that this is a fantasy setup, you'd have to put every piece from the steeda catalog in the rear end and tubular K-member, etc, shave 5-600lbs and get a great driver, I know they drive the 05 stang as a drifter, but it still is just to promote Americans getting into the sport, JDM cars are lighter and can do more with a lot less, leave drifting to them.