Man what a pain in the butt of an install. Getting up behind the junction box tore up my forearms, even with the cover off. Took me about 4 hours to get it installed, the grommet was the hardest part like everyone else said. The key is having a hole big enough to feed everything through. I used a metal fish tape, got the subwoofer wire through and then taped the amp power wire to it and pulled it through. Lots of working in cramped spaces with sharp metal around, my hands are all torn up with little cuts.
Gotta say it sounds pretty damn good though! Not custom setup level but more than sufficient for 90% of people!