There aren't any gains aside from a less muted (and by less muted, you actually get one) exhaust note. Also, the removal of the DPF increases exhaust pressure, and that has to be accounted for.
'09 E93 M3/Jerez Black on Extended Novillo Black w/Aluminum Brushed Trim
WTT 219M 18" Charcoal Staggered for 19" Staggered in Gunmetal, Hyperblack, or similar
Looking for: MS Stage 2 Intake Charge Kit, Metsterschaft GT2, VT1-550, E92 CF Trim, V1