Made up some metal tabs, bent to shape with a hammer and some mole grips, to hold the ends down using the headlight mounting position. And put some screws and a bit of vacuum hose(on the right hand two) through the tabs to hold it in.
You can slightly adjust the screws in and out to align it with the wing/bonnet. Use the vacuum hose to give the right hand tab screws something to tighten up to otherwise the screw can pull the spoiler up too high.
This is on a VR6, I believe that some of the Corrados only use 2 tabs depending on the slam panel, which is why, on my spoiler at least, there were 5 tabs so adapt to suit.
Has been tested to (idicated) 140mph........in Germany of course
Excuse 'winter' condition of car (mmm, heated garage would be nice!)
Andy