Breaking the seal. This is the most difficult and scary part. In order to break the bond the mastic creates between the spoiler and the window frame, you will need to cut through the mastic. Visibility is none existent, and through the centre of the mastic, are the wires and window washer hose. In all likeliness, no matter how much care is taken, you should expect to have to re-join the wires. You should get away with sacrificing a portion of the washer hose, but this could be reconnected using the same type of connector you undid earlier.
To cut the mastic, youíre best off with a long knife. You will need to slide the knife between the spoiler and the glass (keeping the knife blade as flat as possible to the glass) while prising the spoiler up to create a little gap. Take care not to damage the rubber seal this sits on the glass.
You should aim to insert the knife where the wires and hose pass through into the spoiler. Note the distance from the start of the spoiler, to the deflection you saw when trying to pull the spoiler off. Insert the knife a little further than this distance and gently reciprocate the knife back and forth while pushing it through the mastic. You could potentially watch the wires and hose for movement which may indicate the knife is in contact with them then re-position the knife accordingly. However you may well be better off just cutting through them, it will save time in the long run!
Once the mastic has been sliced through, you should be able to remove the spoiler.
If you have surgeon-like skills and managed not to cut the wires and hose, youíll need to feed these through the hole in the frame to remove the spoiler.
Place the spoiler somewhere safe and on something soft that wonít scratch it.
Removing the high level brake light unit. There are two small screws that attach the brake light to the spoiler. Remove these screws, and the light should slide out of the spoiler without any trouble.