Camber Gain
I have the FMJ spindles already.
SPC makes 2 generations of upper control arms. I carry them both. I'm also the only one who makes proper sleeves and spacers to fit the delrin bushed ends into our mopars. The first gen arm uses a stock K772 upper ball joint. Although it comes with stock height UBJs, it can be retrofitted with any of the Howe extended length joints. The second gen arm uses an SPC proprietary joint that is a 1/4" taller than stock. Longer joints and delrins optional here too.
The use of the FMJ spindle is an improvement in feel as it reduces body roll to a degree. The 3/8" taller spindle shortens the moment arm between the center of gravity and the roll center.
Its hard to tell from the photo exactly what the car is doing. The speed must be fairly low and the rear tire sidewall doesn't appear to be distorting. Your comment about adding a rear bar is a good idea as a tuning aid. Since auto cross can have some weird tight turns due to course design, some things may have to worked around. Having experienced may open track days, I'd say some of the setup may be a little different among the two.