Problem is I can't see behind the wall at all, I removed everything I could from the inside , including the ECU and there was still lothere in the way. Was hoping to cut and use a fish line which is why I was asking here if anyone has drilled that spot with success and no damage on the other side.Drilled many holes in firewalls, just make sure you have the proper clearance on each side before you start. I can't speak for the 100 series, but I don't see why that wouldn't work as long as nothing's in the way.