Yea, I plan on throwing some silicone over/around the holes. Also, I used threaded inserts instead of the sheetmetal screws.
For the wiring, what kind of harness do you mean? I'm no expert on this. You mean like wire a post block coming off the battery and tie into that?
I was going to check my fuse block to see if there is an open slot with power when the ignition is on/accessory.