calZ

Sparks from the rear end dragging I believe.

They're canards, essentially. They'll add downforce, but they're so small I'd imagine it'll be barely measurable.

Carbon Signal

I assume that's why this is a project thread.

Have you tested all the other sensors to make sure they're still reading correctly?

Xenonzcar.com has everything you need

I don't think that's his picture, just an example.

Sorry, I should have said two pins that go to +12V and 2 that are routed to ground, with switches or a component in each circuit. Those are their states when the relay is not triggered. I didn't communicate that very well, so that's my fault. Once the relay is triggered, then the output pin has 12V like you said. I'm glad you got it figured out.

Four pin relays have two grounds and two positive, not 3 positive and 1 ground. I could guess at what the wires are based only on that, but you really should be able to figure it out based on the wiring diagram. Trace LY as far as you can and see if it runs to ground somewhere.

If you don't have a step you will completely stop all flow through the radiator other than the circular areas where the fans are. You need some amount of space behind the radiator for there to be airflow.

Almost nothing outside engine parts will interchange between your two cars. You bought a 280zx, which is a completely different car than the 260z or 280z.

What kind of pads are you running? If you're overheating your stock pads, you may be able to just go to a more aggressive pad and avoid the work of setting up ducts.

Often times ducting is needed for road racing. The higher airflow prevents heat soak and fade that you don't run into with short Auto-X runs.

That depends on what you want to do. A single hoop with two backstays? Include an X? Land on the floor or strut towers? The answers will vary quite a bit depending on what you're aiming for.

Speedhut has everything 15% off though Tuesday.