the spherical ends aren't really needed in the lowers, as I understand it...also, not many people realize that spherical bushings "SHOULD" be taken apart at least once a year to clean them for regualr maintenance.
They're a little overkill for the average street car if you ask me. I have the aluminum Steeda uppers and lowers. The uppers don't use a spherical bushing, but they also don't use a solid one either. It's a 3 piece one that can still move better than a solid one can and reduce torque box strain.
The Steeda urethane bushings are hard in the center, but softer on the outside to provide a better feel than just a solid bushing or a hard poly bushing.
Whatever you decide, don't get the BlueOval ones IMO...also, get some damn subframe connectors!