How it secure on tail window?
 

I want purchase that Matting thing, that you can see on top of rear window.
Can you tell me, how it installs?

http://www.golf3.de/images/imported/2007/04/71.jpg

I got MK3 GTI... and there are mounting holes in glass for stock tail spoiler. can I use that holes to install "Mattig thing", or help me to find the way how to intall it... thanks for all.

The "mattig-thing" is glued and called "Heckscheibenblende"... There are no mounting holes needed. I think you have to put silikon or something in your old holes, if you mount this part.

How i can install Heckscheibenblende? how i can fixx it? 2 sided friction tape?

Take some windowadhesive or "Sikaflex" when u can buy it