the 2ltr must be a heavier car (stands to reason I suppose), because whattowcar.com tells me it would be fine for towing the caravan I have, whereas the 1.6 is, it says, 85kg too light. I know there are various assumptions throw into those calcs but getting the 2ltr wouldnt be excessive for normal operation (its what I currently have).
So scrapping the 4X4 notion I think, better value to put Alko ATC trailer control on the caravan (to help prevent snaking) and just using a normal 2wd car.