The SPC/SC&C stuff is good, but can be confusing to choose/config. I did the homework on it a while back, will give my 'opinion', but it may be a little dated.
You can choose a lower tall BJ up to a 1/2" without having to change out the lower control arm.
To get max benefit, you should use both the upper & lower BJs with the upper & lower control arm.
The setup uses stock spindles and steering arms, and the control arms are @ $1200 for uppers, $1700 for lowers:
https://www.spcalignment.com/compone...tion&pid=97110
https://www.spcalignment.com/compone...tion&pid=94344
They might be available from others for less, but those are the prices SPC lists.
You can use a tall spindle upper control arm from other vendors, but at your own risk.
The gain, when measured by amount of additional caster, is nominal (@ 3 degrees).
The original spindles may be a weak point under hard use, 'seasoned' spindles can be compromised (bearing & seal area wear, structural integrity)
In order to do some types of big brake kits, you have to mod the spindles. Also, going to big brakes can push the wheel out making it more difficult to source wheels. (You may even have to change existing wheels, depending on the brake kit, but usually almost all kits require larger diameter wheels)
The bump steer is still archaic and could be improved with a bump steer kit from other vendors.
There is no to little ackerman gains.
The end results is still nowhere near as good as the AFX setups.
You still have to pack wheel bearings, and still have the maintenance, more so in hard use.
My opinion is the GW spindle would be a better option, but it still uses legacy wheel bearings:
https://www.globalwest.net/kit423-ne...1-spindle.html
Not to mention, it's $6500-$7700.
When you look at all the options available, the AFX setup is the most cost effective, and has the best performance gains, without going to a full frame kit. Full frame kits are $12-$15k+.
All new AFX uprights come with the upgraded 'vette bearing, and those are race-ready.
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