Running a power wire through the firewall is a risk. Ensure that if you end up in a situation where your IC isn't running you won't pop pistons. Aka make your tune so it's not relying on it. I'd suggest putting your wire that goes through the firewall to pin 85 to a ground with a switch that you can control. This way as you are loading tunes, you can turn the IC off. Pin 86 can run to an igintion on wire in the fusebox. I like the way PRJ does it by running to a fuel injector fuse. That way if you are loading a tune, you don't have to turn off the pump. Fuel injectors won't be running.
Please..wrap that relay up with a bunch of electrical tape to keep it from getting wet and shorting out. Can't tell you how many times guys come in with problems and I find a relay that got wet, shorted a fuse and caused issues.
