I Hate to p*ss on your bonfire, but I'd say that while €40 is a reasonable price for a badly hacked about N900, I'm not so sure the warranty will cover the stuff like cracked screen and missing screws (a sure sign of mistreatment and attempted repair by unqualified persons).
Chances are the screw threads are still in the holes, making it almost impossible to replace them with new ones, thus needing a case or bezel replacement.

Be interesting to see how it turns out though.