No worries on it hitting the firewall as long as you are using stock motor mounts. Look at the clearance now and then add 1/2" or whatever thickness Chedda's adapter is. That motor sits pretty far forward in the engine bay and when Hasport designed the AFD2 newer D series swap mount they actually move the whole motor back a couple of inches. IIRC you may need a wire harness from whatever car you decide to take the intake manifold from if it is a different OBD. Right now you are pre-OBD but the connectors are all pretty much the same as OBD0 cars. OBD1 have some different connectors, I don't remember which ones, but some are the same just gray instead of white. And OBD2, which is what the Y8 manifold is has some different connectors as well. All the components/sensors work in the same manor, they just have different plugs on the end. You'll have to just go through them one by one to figure out which ones you need to change. You will need the fuel rail because it bolts to the intake manifold, but the stock FI hose should bolt to it. Other than that it's vacume hoses and stuff. Some stuff on the manifold you won't use, like on the Y8 the map sensor is on the TB but yours is on the firewall so you can just buy or make a block off plate. Also not sure about stuff like the idle air control valve, you may be able to wire it in, i believe the old idle air control valve was vacume operated. Take your time, ask lots of questions, and do a good job. If you do it you should do a write up and it would make it easier for others to follow your footsteps.