Really? I think that if he changes the interiors of the XFG, XRG and FBM noone can say anything.
I don't remember license-protection over the .dds files.
He can't use THESE files, because surely the Scirocco (when it will be released) will be reserved to S2 players [edit: I was wrong, it will be reserved to S1 Licensed].
So, Scribble-1990, try to ask how to use the .dds files in a XFG/XRG/FBM modifications related topic, surely someone will be helpful there without being just suspicious and not really nice to you
Or, better, use the Search button... You'll find surely something!