Vector-what i was trying to say was that if you let off the gas a little bit while sliding it'll keep the rear end from walking around because it's spinning from excessive acceleration. Letting off completely will disrupt the balance as well as braking (mustangs have horrible 60/40 weight distribution and the engine is located right above the front wheel axis). Braking pushes weight to the already heavy front and as a result the rear end gets lighter and the front end acts as a pivot point for the car (around a corner most of the weight will be over the outside front tire). As for porsches and other cars doing 4 wheel drifting, the cars are 50/50 in weight balance and have better suspension geometry than the mustang and well as less ground clearance and stiffer suspension, Rally racing strategy is quite different than Road Racing because a Rally car usually is Front or all wheel drive and they use the brakes to shift weight and whip the rear end around. I may be incorrect but any kind of sliding in road racing is considered bad because it actually slows the cars down, where as in rally racing to get quickly around corners you want to be able to whip it around while still accelerating.
Are there any autocrossers or Road racers here? The only experience i have is my own driving and reading a few suspension and better driving books, so i may be wrong.
------------------
'84 Mustang 5.0 LX
My car