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.
'98 M3, track beast
'06 Porsche Cayenne Turbo S 521hp daily driver
'07 KTM 990 Adventure