Inlet manifold mods

Swapping the SU inlet manifold on my P6 as the old one has the bleed pipe blocked beyond belief.

Apart from matching the manifold to the gasket, is there anything else I can do to improve flow? Apparently throwing away the swirl devices helps, don't think I even have any of them...

or is it not worth bothering about. Tis a 3.5 with SD1 heads, will have free flow filters and a decent exhaust, and a little porting on the heads and possibly a cam some time in the future. So is it even worth it?

Cheers!