just take the roof lining out mate i think you might find the sunroof inner tray is rusted through,had this on a few of mine,with the one im doing at the mo i opted for a complete carbon fibre roof check them out at WWW.CARBONDELIGHT.COM, it does away with the whole roof 4 inches from the gutter,i weighed the original roof when chopped 23kg and the carbon one was 3kg.but you do have to have a rollcage for obvious stregthening reasons.