Re: 2007 GT3 LATCH system
I will try to get photos this weekend, but I'll answer your questions now as best I can.
(1) The install is very clean. I have to tell people that I have LATCH for them to notice. If you lean the passenger seat backrest forward, you can see the color-matched metal plate that goes across the back of the seat bottom. Again, you have to be looking for it. You really can't see the loops protruding between the seat bottom and back. If you look hard you can see slight separation, but again, I have to tell people that they're there for them to know.
(2) The anchor points for the loops are provided by the metal plate that covers the back of the seat bottom. Picture a solid sheet of metal, formed to match the seat bottom, affixed to the seat at the sides and covering the back of the seat bottom, with the loops prodruding along the seat bottom through the slit between the top/back and the bottom of the seat.
(3) I thought that all of the LATCH latches were the same, so I can't really comment on the Britax (I have a Peg). However, I have no difficulty sliding the catches in and out between the seat and backrest to latch them. The loops protrude enough (though not visible) to make this easy.
Hope this helps. If anything is unclear, let me know.