HPF.i have it & has been great.The others are great too.dont think you will go wrong with any of them.I can only speak for the HPF.Nice perfect fit.
E90 SEDAN '08
-STOCK TURBOS FBO AT*FSB G5 ISO*100%METH*DUAL CM10/CM05*FUEL iT!STAGE2*ALPiNA FLASH-
-NGK PLUGS*BMS OCC*RB VALVE-
-E85 MHD CUSTOM FLASH-
HPF V2 EXHAUST