As far as I know self tapping screws will do the job. My laguna one is held on with self tappers.
just go to nissan will only cost a few quid and then you will have the correct ones.
Thanks for the info. Do self tappers come in different sizes though?
what colour is your car? personally any other colour than black i wouldnt bother!
For the same effect, get a laguna splitter or a seat leon cupra splitter.