Josh and I have a project on the go. New bolt on manifolds with hopefully either a flange that will fit TD04's or a flange that will fit T25's/T28's(your choice of flanges) with no modifications to the firewall.
We are hoping to have a prototype made up by August/September, I'm going away for a few months and so is Josh so thats going to slow things down quite a bit.
Yes, you would need dumps to suit the turbos you fit.
They will be made from seamless hot formed thick-wall steam pipe. More specifically ANSI 48x3.6 (40 nominal bore) carbon steel pipe (melting point of 1450deg). This pipe has the ability to be crushed flat in a press and still show no signs of cracking without any heating which is also proof they are seamless given that there are no weak points. There are also several bolt holes that are not used on the side of the heads that we plan to brace the manifold with 6mm round-bar and M8 bolts in 2 places. That should be more than enough to hold a 7kg turbo working at 800deg!
purchasing one for the missus rex this weekend and will check to see physically how much bigger they are, but 6a13 engine bays arent exactly friendly for space, if they did fit it would be FUC*ING amazing though