Also pondering this question, and wanted some real world experience so went to youtube and found this video that compares 2 systems on an engine via a dyno, tracking and analyzing the results.



So with my Nomad engine being a bone stock LS1 (about 340 horsepower) and the desire for quieter (3 chamber mufflers), I'm wondering if I need to bother with a 3 inch system?
Either diameter size would fit (with the thru frame AME cross members I have welded into my frame).

Let's hear it guys, what's your real world experience with 2 1/2 or 3 inch exhaust?