that data is meaningless if its done with two different engines, engine outputs can vary greatly between the same engines.
had the Toda V2 18c header and found it great power all across the rev range....a noticeable difference in low to mid range power over the 4-1 DC sports i had on before, However top end i felt was similar if not the same.
one thing to note is that the header itself is extremely lightweight for the chunk of metal that it is, was probably half the weight of the DC sports 4-1 i took off.