You have two ways to do this, get the whole front clip from the donor car with the engine attached (This way you have the wiring harness). Or make sure you get a harness with the new engine. You will also need the computer that goes with the donor engine. Most of it is plug and play as long as you have the correct harness, there will be some splicing with lights and engine accessories and guages, but nothing major. Check with the performance shops first, I'm sure someone manufacturers a wiring harness ready to go.
Cost is hard to say, if you are doing it yourself its considerably cheaper as long as you have the equipment and know how. For a shop to do the work......$3000.....I am not too sure.
