currently rebuilding my cosworth, looking to get 450bhp and was wondering if i am on the right tracks. Also thinking of getting siemans black 83lbs injectors, do i need to get the siemans chip to match?

current build status:

200block 6 studd mountune kit
wrc multi layer head gasket
ported head inlet 25mm, standard exhaust side.
standard crank
mains studded
wrossner pocketed pistons with uprated rods
piston calling jets
wasted spark
double valve springs
bd14 inlet bd10 exhaust
turbo technics stage 3 turbo,
7° cutback T3 turbine assembly
360° screwed thrust bearing.
do i need to get a billet manifold?
would this be able to achieve 450bhp? any help will be great.