From the negative post to a bolt on the intake (a silver coloured metal tube that is in front of the intercooler and is about 2-3" thick. It is ~15" to the left of the negative post. The bolt on the intake already has a wire going to it. The bolt is located at/near a
90 degree bend in the intake. It is very obvious as to which one it is. Go to the Nasioc link earlier posted. There is a picture in the last couple of pages that is pretty clear. The picture shows a number of connections daisy chained around the engine. It probably isn't necessary to do that. The one connection was enough for me. Today I put in a #4 wire that I bought at the autoparts store. It was premade 18" long with a couple of clips. It was made to connect a starter to ground. I just used a cresent wrench to take the bolt off the intake, cleaned things up, bolted it down, and then applied some dialectic grease with a disposable brush. Same thing with the battery terminal. I also cleaned up the ground to the inside fender right next to the battery.