@bill_b mike bambic is over at ecopowerparts.com and makes kits for 18 up Navi and expedition. Here’s his description. Looks like you keep shocks and add his coils
“Our lowering kit is a 2"/2.5" set of lowering springs made custom for the 18+ Navigator and Expedition. I can only get them made in single sets at a time with 10 business day manufacturing lead. They ride well, 15% stiffer than stock but do bottom on the bump stops over speed bumps but cornering is much better than the super loose ride from stock.
If you have the CCD suspension (check your build sheet) you'll have to get CCD suspension adjusters from another vendor I was unable to secure the rights to wholesale/produce myself on those.
Email
[email protected] if you'd like an invoice sent over to purchase. the price is $875 for the set of lowering springs.”
Hope this helps yall