Just to add few cents worth on info:
Chassis setup and tuning is not directly related to where the driven wheels are. Principal physics are the same for all cars.
There is no such thing as eliminating weight transfer front/rear, side/side. No matter what is put on a car, weight transfer is always the same. Suspension geometries, A/R bars, or springs, etc. do not eliminate weight transfer. For example, a go-kart has no suspension components at all and it is one of the vehicles that is effected the most by weight transfer due to its small size and overall weight.
Suspension systems are used to "manage" weight transfer to make the car handle better in a given situation. So, what does all this mean?
During cornering, weight will be transfered to the outside wheels; however, the question is can you get this additional load for higher grip on the outside without loosing too much inside grip and without deforming the tires and alignment. Body roll, deflects wheel alignment relative to the surface by adding camber. This positive camber results in higher tire slip angles. As you would know, a certain degree of tire slip angle is a good thing, usually between 8 to 12 deg. However, if body roll is excessive, you can get as much as 3-4 deg. positive camber. Obviously, this is not a good thing, hence you want to minimize body roll. The rule of thumb is to limit body roll between 1.5 to 2 degrees under 1g cornering force; higher for street cars and lower for higher-performance cars. F1 cars for example have less than 0.2-0.3 deg body roll at 1g, but they are also able to pull much higher cornering powers, so you will sometimes see noticeble body roll on them as well.
Obviously, the "anti-roll bar" is one tool to combat body roll. The biggest negative about A/R bar is that it makes the suspension system not so independent, and we sometimes get a result in which the inside rear wheel takes off the ground during hard cornering as you have mentioned before. That is definetly not a good thing, and means that rear A/R bar is too stiff. For this particular reason, many club racers and specifically F1 cars before 1995 did not use A/R bar on the rears.
An alternative way to manage the weight transfer is obviously the springs. With higher spring rates and stiffer shocks, you can reduce body roll, and in return you give up comfort
But more importantly, if you have too stiff of a setup, the car would be too bouncy for certain roads, and you just cannot get the power down enough to take advantage of the lesser body roll. In this particular scenario, a 4WD setup helps as there is power at some corner on a bouncy tarmac.
Adding negative camber is a very popular way as well, but how much camber will you keeping adding? I personally would not put more than -2 camber on the fronts and -0.5 on the rears of the STi. The downsides of the any camber are reduced braking capacity, reduced straight line stability, and increased tire wear. Hence, keeping camber adjustments sensible and managing weight via the combination of springs, shocks and A/R bar has been the preferred way for several decades now
Specific to the STi, I do not have the definitive answer at this time as we just received our development STi. We will be running tests for the next 2-3 months and hopefully come up with multiple ways to modify the suspension system per driver preferrence.
I do hope I did not bore anyone reading this, just wanted to add some information.
Thanks.
