Originally Posted by Blaque_Out
I don't think anyone without a shop and race experience would even dream about making their own manifold however
The IC pipe that leads to the throttle body however would be easier to construct.
I am assuming that at the point where you would replace the IC pipe, you are equipped with the B235R intercooler and that you are replacing the IC pipe with a larger diameter pipe.
Realize that increasing the volume of piping between the turbo and throttle body will add turbo lag. This is the reason why WRXs use a TMIC rather than a FMIC.
The major restriction in the FMIC to throttle body path in the B204L is the throttle body transition casting. If you have already performed the port and polish on this piece you know that the inside diameter narrows at the bend. However to replace this with a mandrel bent piece will require more clearance at the hood.
This is one place where Saab really screwed up in the motor design. By orienting the throttle body vertically, the intake manifold requires an additional 90 degree bend to flow air and they were forced to flatten the TBTC for hood clearance.
Ideally you would mod the intake manifold to orient the throttle body horizontally and then mandrel bend the IC tubing from there to eliminate the TBTC. Then air will flow more easily into the engine. Modifying the IC tubing w/o dealing with the TBTC restriction is a useless mod.