HMSmikesS2K

When on the modifry website I get confused about what I need. I see a DCI harness and a PNP harness. My concern is that i want the dash controls to still work. So i would assume the DCI harness right? But then what is the PNP harness for? I already have a radio harness for a s2000 but with out the extra wire for the dash controls. Cant i just cut the few wires on the dash control and tap them into the wire harness I have for my head unit. Basically same thing as the DCI harness but yes i know I would be cutting my wires. Not a issue for me. So in this case Where would i tap the wires from the harness off my dash control into? Im sure plenty of people have done this so just looking for input, opinions and answers. thanks