I tried searching for where to source an exhaust manifold, but all I found was the HKS units which are either cast or 304 stainless, and I was looking for something that's 321... Maybe I need a custom job, does anyone have any suggestions?

Secondly, I was wondering if there was any way to find out the flow/pressure drop of any of the standard front-mount intercoolers (i.e. apexi GTR core, greddy 3-row)

thanks for any help,
kyle