NO-ONE, but no one knows more about smooth riding, deft-handling suspensions than Peugeot. The French charms of the 406 model appeal to drivers wanting a touch of individuality and with an update not so long ago, the cushy Peugeot looks and feels better than ever. The SV model's V6 is a fluid, smooth performer but the sluggish four-speed auto is its Achilles heel. The optional five-speed manual transmission is a better - and slightly cheaper - proposition.