Do I really have to pull out the wires from the factory harness that the instructions say to pull and why..

 

You either have to pull the 4-pins or cut/remove the wires. The car will run like crap if you don't. It's better to pull the pins IMO, but I guess most people just cut the wires. Be warned that the harness is like $600 at discount pricing and is obviously a pain in the *** to change.....

 

what are the 4 pins for that I am removing.. I dont remember doing this on my last fd and it ran fine...