Hi everyone, I'm looking for advice on upgrading my rear suspenion on my late model 2003 Expedition 4X4 EB non air.

I've noticed the rear is softer now, and sags. It's not too bad when I use my WD hitch on my Travel Trailer - but as I live in the U.K. all of my other trailers (cargo type) are not designed for a WD hitch and it sits quite low, even without much weight on. It also does it when people sit in the 3rd row.

I'd like to change the rear springs - are there any adjustable type available? or is there an air helper that would fit? (the only ones I hae seen, do not work with the springs with the shock in the middle)

Also, I'd like to improve the sway bars - any makes to go for?

Thanks for any help