Disclaimer: Do this at your own risk!
This is for cars with through-loading system. If you do not have this, you will need to remove the rear seat back.
I also need an interior detail - I have brake dusty fingerprints all one the back seat from swapping winter wheels. I never sit back there, so I didn't notice until the photos!
The removal is fairly straightforward, just a few steps to get in the correct sequence. The only real pain was putting the shoulder trim back in because of the airbag release clips. I dropped one on each side. At least when I get a rattle, I know where to look now. I'll go get them when I get the urge.
The seat anchors are installed the same as in this thread from Bigjae: http://www.m3post.com/forums/showthread.php?t=674335
My first impression sitting in the stationery car is that your hips are absolutely locked in, but your upper body can move around a bit with the long pivot to the rear, however, once you are strapped in and driving, you are held pretty damn solid...much more than a CG lock or "locked off" stock harness. Once you get used to leaning into the straps, it really stabilizes you and you hold the wheel with your fingertips even on tight bends. You can really feel the weight of the car move around, especially the braking as you feel it in your ass and also now on your shoulders. It does change your ride. After a couple of commutes, I am used to having the harness there now, and tight bends become a lot more fun when you are not hanging on. The compression feels a little odd, and you can't move around to look in mirrors (an old habit of mine from the UK) as much. I am looking forward to my skid school tomorrow.
You absolutely need the accessory grips for the pull down and waist straps if you want to get tight. I would recommend the extra padding for the shoulder straps if you have a thick neck like me. After a couple of tries, the best way to tighten the lap is to tighten while sat in the seat, unclip, tighten the straps a little more and get back in and leave the lap belt at that setting and clip in. I found that tightening the lap belt first with the shoulder straps off makes it much easier to line the lap belt up, then pulling the shoulder straps your shoulders and pulling tight. If you have the shoulder straps on while tightening the lap belt, it has a tendency to pull the lap belt up and get the alignment with your hips wrong.
Anyway, so far, so good. Hope this helps someone else out!