Doug : the Wilwood spindles are just cut-down stock cores. All of the cutting is in the area around the caliper, nowhere close to the suspension joint contact points (balljoints and tierod) on the spindle. The upper balljoint spacer won't affect them a bit.
Only issue I see with the spacer is that 17" rims minimum will be required in front (to clear the relocated upper balljoint), and it may require 18's. It will take some trial-and-error with the mock-ups on that one. Chris : this is something the vendor should look at, e-mail me offline if you need more info.