yup. the larger tubes are called plenums, and have a specific volume which helps the torque at a certain point in the rev range.
The smaller tubes (intake runners) are 40mm in diamater, and of a certain length, again to provide a boost at a different point in the rev range.
what brian didn't draw on his etch-a-sketch, was that the xe throttles have a length of tube in front of them. the length and diamater is a means of tuning the revs range over which the plenums are effective.
Injectors are the easy bit, we'll make up bosses for them, and weld them into the intake runners.
Hopefully, it'll be finished next weekend!