i'm think of cutting my seat to add a din dvd player .in the back seat of my suv the center seat does not move so i'm looking at that seat.it would be on the face of the seat where your knees are.is there something i need to know be for i start?

 

I don't think you should have much to worry about. If the depth is there & someone sitting on the seat does not compress the DVD player then as long as you can mount it securely you should be fine.
A staff member at one of my accounts did this in his Golf a few years ago:

http://www.ralphsradio.com/general.asp?id=50

Good luck!