floor should be screwed down.. otherwise engine box (dog house can slide and collide with front of spinning engine parts...
Mike its a friction fit. My 02 209 was the same way. Became a bit annoying. The carpet is obviously going to compress over time and not fit as well. The back fit is not the problem its the floor fit where the dog house meets. My carpet eventually started coming apart from where it would pop out etc. Make sure you have the front of the doghouse locked down in the front at all times. What about a thin layer of clear silicone on the wall of the floor key?