I went with a 2.5 inch straight pipe with headers and I REALLY noticed a difference in low end, BIG lose. Every N/A motor needs some back pressure, and just like a SBC, there is a sweet spot to place the muffler for peak performace. Keep doing some research on back pressure before you make your decision. I wish I had put in a muffler, but I'm going turbo, so no need to change up now.