Are those PipeMax diameters the tube inside or outside?
I was guessing 2-1/4 tubes, which is OD, so assuming 18g (0.049 wall) that is 2.152 nominal ID.
I believe in the step header design, just a little bit more work and typically material waste.

1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1