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The front anti sway bar acts like a torsion bar from one lower control arm to the other.


yes. and its's attached to the chassis at the K frame. Rear bar is same idea.

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The front bar prevents the outside tire/body, from diving too much, while lifting the inside tire at the same time.


Basicly yes. Simplest description is that it helps fight body roll. That's not usually described as 'dive', but it sounds like you have the concept. Rear bar does the same thing but on the rear.

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A front bar tries to prevent body roll but will actually cause one of the front tires to break free of the road surface during understeer, and a rear bar could cause a rear tire to loose traction during oversteer.


You're mixing things here.
Understeer: When a vehicle doesn't turn even though you're turning the steering wheel. Plough.
Oversteer: When the when the vehicle turns more than you think it ought to. Begins a 180.
A Sway bar will increase the load on the outside tire and reduce the load on the inside tire. This will reduce overall grip when the tires are already near their limit of grip. However, this is often ofset by things like better tire geometry in relation to the road. For street use, you are not driving at the limit, and the car will feel more stable and predictable.
Too big of a front bar in relation to the rest will result in noticible understeer.
Too big of a rear bar in relation to the rest will result in noticible oversteer. If you get into an oversteer situation on the street, especially on wet, downhill or curve, you're pretty much guareteed at least 180 into the curb or ditch.

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Front sway bars are available as a bolt on after market part.


Yes. But there is some variety to how they address the attachment to the control arm. There also is variety in bar diameter. You want a diameter that is the in the ballpark of the rest of the package.