OK, after a week of perfect weather in QLD on holidays i took the oportunity to pick up my hand built mufflers from Gonzo, who is the exhaust guru. These are his new trick mufflers, and like i said they are nothing like you would have seen before. They are 3" merged into twin 3" pipes but with the spiral vortex baffles welded inside. They excellerate gas flow while muffeling sound.
Gonzo also had a software programe on his PC which after entering some engine specs gave us the ideal collector diameter, merge collector area and ideal dinstance from collectors to merge collector.
All of this aids in throttle responce, torque and peak power. Hope to have car back soon to fabricate exhaust and other tin-work etc.