I have a Greddy T78 downpipe and found a source for a used SS manifold. Although I'd prefer cast iron manifold for longevity, this is a geniune Greddy from the T-78 kit (as is the dp) so I figure it should last.

So I will be shopping for a turbo and WG. I am considering options other than the T78 since there are many that use the T04 flange. Since everything else (ic piping, oil supply & return, intake, vband dp mount, etc) will be custom, is there anything about this manifold that would require using the T78? In other words, is there anything keeping my from using another size turbo with the Greddy SS manifold as long as it has a T04 flange?

Thanks,
Chris