Yea I think he buys the header's and throws his name on it and sells it locally.

I know at least for the H22 Hytech and RMF replica header's are made somewhere, then businesses buy them from the vendor and sell them under their own name.
I seen it done with lots of different car parts before.

I am pretty sure KiDDRacing doesn't currently make headers, he just sell them.
IIRC.