Dead useful little fasteners that discovered at Autosport this year, called bonding fasteners http://www.bighead.co.uk/english/products/index.html
We use these all the time on GRP for fixing panels together only as strong as the glue you use, we use plexus with a primer added first makes these very strong.
Just ordered some of these to attach my front splitter to the car after grinding the dome head bolts off clean on the track.....so are going to thread one of these up from below through the splitter and cover the base plate with a piece of kevlar/epoxy. Lets see if that resists track grinding..... Probably would be best just bonded to the top of the splitter but I just dont fancy risking that. Apparently the M6 mild steel version will withstand a 550kg force, so they look quite robust.
I'd be tempted to bond from above and use maybe 4 small countersunk screws from below you're going to smash splitter before it drops off
The rectangle shaped one to the left looks like it could used to fasten the side trims on. I was thinking of aralditing bolts to mine. Heard of people robbing them and then flogging them on ebay etc. The trims would bend or snap if someone tried stealing them. If I cant have them, neither can they lol
