do coilovers put more stress on balljoints?

I wouldn't worry so much about the balljoints as i would with the top of the strut towers.

I'd say investing in quality Caster Camber plates is a must with coil-overs. It's do a STB as well. Max Motorsports would be my recommendation on both
 
Maybe this true but arent coil over springs lighter in spring rate than the stockers?


still wont effect the ball joint... if anything.. the lighter spring is better for part longevity because the harder spring would exert more force to keep the tire in contact with the road and over the coarse of the lower Ball joint life span it would see harder impacts over bumps...where as the softer spring would absorb the jolt and transfer the force into the dampener(shock/strut).