[vettestr]

OLDDOG = "There has to be a way to keep the suspension "at balance" to allow good performance both directions..."
No it does not have to be 1 or the other but a compromise is giving a little here to get a little there and nothing wrong with that.
Highplains is much more inspired to the drag side and he is right in claim Advanced ET cars must have a solid axle and dis-allows IRS but that alone does not make it a bad choice for a Cobra, Vette or other performance suspension.
As a point of reference the Olds Toranado mentioned earlier is an absolute torque monster and a real tank (very heavy) it has a non solid axle. I agree not apples to apples here but a paralell theory ...kinda?
If I was building a drag car it would have a solid non sprung axle and my Cobra inspired cars have an IRS but that just means I won't be stealing highplains extra parts and visa versa so life is good