I'd absolutely recommend getting the diagram but be prepared to make some modifications to match your vehicle! (I assume the factory wiring evolved in areas with time and not sure when the diagram was made). Worst feature is the tiny size - I had it enlarged to 3 x 5' which helps a lot. All in all PLENTY of confusing and/or incorrect details, and wire colors are not noted. That said, the only part that was totally missing was the emergency flash relay, which on my car is under the dash, beside the horn relay. Still, a huge help!