Doubt it. The BW 3.5" exhaust seems to be one of the main keys to making 340, but it's not really street able. You should be able to hit 310-320 though.
No one is really doing custom tunes for the E46 M3, Epic is your best choice.
'89 Porsche 944 Turbo LS1
475hp track beast
'03 Audi allroad 475awhp daily driver
'03 BMW F650GS Dakar