I had that on my Lupo. The pedal box ended up going through on me. Its a safety measure for an accident, just a pity it makes the pedals quite weak. Have a look at picking a pedal box up, their not too expensive from VW.
http://www.ebay.co.uk/itm/VW-LUPO-98-05-REAR-SPOILER-/150639427990?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2312cf4196 This spoiler is immense looking! Especially matte black on my light blue Lupo. I ca get photos up if you need. Defo the best spoiler I found.