We have travelled with two adults, two girls aged 11 and 12 and a cairn terrier and a large suitcase without any steering problems at all. Of course, the car feels a little different when fully laden, but the main problem have been too soft dampers and soft rear springs. I have changed to 195/65R15 tyres to gain 10 mm ground clearance and fitted AVO dampers up front. Now I am getting new AVOs fitted at the rear as well. If this is insufficient, the next step is to get stiffer rear springs.
Harald