Clearly your "SOUND ENGINEERING PRINCIPLES and experience" come from years of tuning LS1's, AND from trying countless different combinations of exhaust systems for this particular engine.
I don't have an "opinion" on this subject, I just have my own experience.
The reason I originally posted in this thread was because of your "1 5/8 pipes are
far better than larger pipes" statement. This statement annoyed me somewhat, because quite frankly, it's bull.
I was going to just let this ride until I saw the statement I have quoted below.
Quote: "Even on the race car ( which produces far more HP & torque than you will see in a Cobra road car ) the primary tubes are still 1 5/8 to maintain the low down ( below 4000 RPM ) torque."
This quote just cements my belief that you are just out to "flog your product" even if it's not really the right product for the customer!!!
I guess you are also right about my tuning skills (that are not worth a pinch of ****!). Because of the lack of drivability below 4000rpm, most of my customers have to drive around in 2nd just to keep the revs up! Just ask Aussie Mike, Leeroy and snkbte (all who have CR's by the way) from this forum, I'm sure it annoys them no end
EDIT: If Bretts car is the one I am thinking about, we managed to screw more than 50 extra hp out of it AND make it WAY more drivable. After fitting all the correct sensors and equipment of course.....