As I mentioned earlier, the injector manifold I purchased just didn't fit. So I decided to scratch-bash a new one. I made the manifold itself from scratch, then used the injectors from the resin piece. I think it's going to work.
The piece on the left is the one I made, the middle is the blower manifold that came with the kit, and the right one is the resin injector.
I added some ribs and a distributor location.
Cut the injectors off the resin part.
And the final part.
Thanks for looking!