Originally Posted by bdaddylo
Stock rear sucks compared to any aftermarket no matter what midpipes you're running. I believe the stock rear is more restrictive than the stock midpipes.
Not from my experience. The midpipes (MadDad) on both the 135i I had prior, and the 1///M added a lot more power (10whp/8wtq), than the rear cans (MadDad in the 135i case, Akra Valves open in the 1///M case, both of which were between 2-4rwhp, in fact the manufacturers state that).
The stock midpipes are definitely more of a bottleneck than the rear can, relatively speaking.
PS: perhaps that also explains why the N55 engine is rated at the same HP as the N54 as the loss of one turbo is partially offset by a frier flowing midpipe.
2011 BMW E82 1///M: AW, all options; Renntech, Akrapovic, Forge, P3, RevoZ CF bits, many mods
1988 BMW E30 M3: Hennarot, S14, stock
2016 Porsche 981 GT4: Guards Red, LWBS, SC, full leather
1998 Porsche 993 C4S: Zenith Blue, last aircooled widebody, Bilstein PSS10, Fister II + Fabspeed exhaust
2008 Audi B7 RS 4: Sprint Blue, Audi Exclusive Euro Bucket Interior, Premium+Titanium, many mods