[MnMadhouse]

With it installing on the back window is actually okay. Make sure you tether the seat. I had a situation similar to this and when I called britax (and being tossed around to a few people), it was concluded that it is okay as long as it is installed correctly.

The family I was helping was concerned about the window breaking and the seat/head getting all torn up in the case of a crash. Safety glass is made to crack into tiny pieces, but stay together. With it touching the glass, I would also likely get a new seat when the top of the child's head is even with the top of the seat--just for extra safety measures.

	Britax - Click for more info Britax International has been producing reliable child safety products for over 30 years. Not only does Britax have decades of experience creating car seats and other children's safety equipment, Britax has a long standing reputation as an industry leader and innovator. Britax International is headquartered in the United Kingdom, but Britax car seats are designed and manufactured at facilities in Germany, Austria, and the United States. In the summer of 2002, Britax strengthened their commitment to creating the safest car seats with the opening of a brand new, state-of-the-art crash testing facility in North Carolina. Britax car seats have a reputation around the world for being some of the safest, most reliable, and best designed child safety seats ever made.