I need new seat cushion foam padding for driver seat and front passenger seats.
 

I'd prefer to buy OEM foam pads, but I'd consider aftermarket foam padding.

I need seat bottom and back cushion padding.

My Park Ave is a 97 Base model, but it's current seats are junkyard seats from a later model Ultra. I think maybe from a 2000 or 2003 Ultra.

Where can I buy OEM foam? What part numbers for foam for type seats in photo below?

Under the circumstances maybe just upgrade again to even later model seats? If that bad, spring webbing may be sagging also and/or frame warped. Car itself isn't new by any means and by the time all's said and done may prove a better fix?