... Place a splitter on the the front bumper, I purchased one sprayed it up all nicely and now I wanna place it on.. been reading up and most say self tapping screws i'm just abit scared when I put my foot down it flys off lol.

 

Self tapping screws will hold it on fine.

 

Yes, DECENT self tappers, get some stainless ones from Screwfix, mine were the ones with countersunk heads and were fitted in stainless screw cups from the same place.

And when fitting, DO NOT overtighten them! You are only screwing into plastic, overtightening will simply rip the threads apart and lead to your spoiler flying off at speed........
Tighten until the screw is seated, then stop. If using screw cups, they should not move.