THE heart of any Peugeot is its suspension system and the 406 is a perfect example of the company's art. The system comprises "pseudo" inverted MacPherson struts at the front with lower wishbones and a de-coupled anti-roll bar, and a fully independent multi-link layout at the rear. The secret of how it all works is in the careful location of linkages and choice of spring and shock absorber rates - a formula that still eludes many suspension designers.