Hey Mmasse.
Xsaras, like many French cars, have torsion bar rear suspension which is not easy to adjust. It can be done by yourself, but it is very tricky as the bar is under tension and you have to turn the bar so many notches and make sure it's the same both sides. It's much better left to a garage, which is what I am doing. The front suspension is easy enough as it's MacPherson struts.
You can lower the rear without changing the dampers (gas struts) and just using lowering springs at the front - it's much cheaper than a full suspension kit and my friend has done this to his Saxo VTS and it rides and handles fine and much better than at standard height lol
You can get Haynes manuals from Halfords which are always very good to work from.
Rich :silly2: