2004 reg E46 M3 is £215 for 12 months, as the government deferred the tax bracket increase for '01 to '06 cars until 2011. It's only the cars registered after late March '06 that currently pay the £405 for 12 months tax

Here's the Parkers link with current info on - http://www.parkers.co.uk/cars/road-tax/?deriv=22102