Hi Dondoleo,
The steering rack is relatively easy to replace, pinion loose, four bolts and the two steering joints, ofcourse you have to drain the power steering oil first. Only thing is, ýou'll need a replacement (refurbished) one, which is pricy and you have no choice really. After that you have to align the geometry again.
But I wonder, clunking can be many things as already pointed out. You also have a torsion bar held by rubber bushes which could be worn, at the end of the bar you also have short reaction dampers which hold on to the wishbones. These are also fitted with rubber and can rattle over time.