My buddy has a brand new set of dragon fire door lowers for an XP4 1000. $415.00. Retail is about $500. Located in Claremont, Ca here's a link to them for reference.
http://www.dragonfireracing.com/product/1379/4-seat-rzr-door-panel-and-slammer-kit
http://www.dragonfireracing.com/product/1379/4-seat-rzr-door-panel-and-slammer-kit