Since the important factors in exhaust tone are:
Firing order (assume 153624)
Cylinder size
Cylinder pressure (torque)
Compression ratio
Exhaust valve opening point *earlier is louder)
There has to be some combination of parts (lengths, diameters, boxes, resonators) to make it sound like an XK-E (or my Lexus 2JZ 3.0 liter)!!
