I need help finding better than stock rear lower control arm (spring seat arm) bushings. I can't find anything other than stock.

The only thing I can find are these but stock appearing:
551B0-1BA0A ? ARM BUSHING FOR REAR ARM - Febest #NAB-330 - One Year Warranty?

I was hoping for something harder like a urethane sway-bar bushing type.

Like this in urethane not solid and, of coarse, rear:
SPL PRO Front Lower Arm Bushings - THMotorsports - Discount Performance Car & Truck Parts Sale | Lowest Price | Free Shipping