You can get an Bosal or Ansa rear muffler-little or no increased noise or benefits. The Eberspacher is an OEM option with a sporty tone, but still quiet. Supersprint gives you the benefits of stainless steel, sporty tone, and slight power increase. Many videos on youtube show E30s with Magnaflows mufflers. If you go that route, there is a fine line between increased noise (drowning), lower back pressure, and increased horse power. Losing too much back pressure can result in a loss of low end torque. This might be what you're feeling.
Big Boyz with Bad Toyz.
Last edited by BigBoy740il; 02-03-2013 at 10:33 PM.