After seeing what the angle of the ball joint looks like with the shock boot off when the factory suspension is lowered, you might consider other options. Maybe it works ok but I sure don't like the look of it. I can post a pic if you like.
Maybe you don't like the look of it, but works just fine. I have had zero ball joint issues on my cars, and all of the ones on the road are lowered significantly.
Not only that, but your suspension geometry is just as bad with drop spindles. Not at the ball joints, but everywhere else. I ran drop spindles on my Challenger for awhile. I'd never do it again. They're unnecessary (my challenger sits just as low now as it did with drop spindles), and the suspension geometry is better without them. The best roll center, camber curves, and bump steer numbers occur when the UCA is roughly parallel with the ground.