I'm about to get a Procede tune and I'm currently running stock downpipes, midpipes, and a Remus race axle-back exhaust.
I understand downpipes are a great upgrade for performance but I defintely won't pass smog. So I'm thinking about freeing up some air flow in the mid section and getting a better sound by replacing the stock midpipe which has the secondary cats and resonator.
Do I go with straight midpipes (Borla or SuperSprint) or an X-pipe with connecting pipes? I'm not sure what the diff would be but the x-pipe set up is more expensive?
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2007 335i e90 - black on black w/wood trim and iDrive
19" BMW M-Performance wheels, ST coilovers, m3 rep front bumper and skirts, CF Hamann rep diffuser, Remus Race quad exhaust, aFe DCI, LED angel eyes & DRL kit,