If I put a set of PD150 injectors into my PD100 engine, will they need to be coded to the ECU to work? I know I will need a remap, but just wanted to check if they are coded or not.

Nope - plug & play. But they will need someone who knows how to fit the PD injectors and set them up correctly.

You getting a bigger turbo as well to complement the injectors? The injectors will provide enough fuel for 200+, but the stock turbo is a wuss. I recommend a pd130 one at least (cough, search Ebay for "low miles PD130 turbo" as that one will bolt right on )