strange question about a Picnic

[adamcress]

Hi all

I've got myself another toyota after awhile without ( used to have a black RX30 with 4M fitted ) I do a fair bit of towing but find that the rear sags under weight so I've found after a bit of looking that the Picnic , the Ipsum and the Sienna all use the same rear springs and dampers ( same toyota part nos. ) Anyway my question is does anyone know if air adjustable dampers or an air helper spring to fit a American Sienna would fit a UK Picnic ?
I'm getting fed up of draging the towbar and exhaust on speedhumps with the caravan on.

Thanks Adam