To avoid the one pic rule on that other thread here's some images to help you mull over. I've tried to find some shots of the car in relatively the same angle and position, the below is the best I could find.
The below is what mine looked like with flat sides.
vs
I did a small pull on the rear wings before I went to the GT wings. This was because I but on 6 inch minilites and some hefty forest tyres on them which had extra heavy duty side walls with anti-puncture mouldings which rubbed on the wing on near full travel. I made a contraption that attached the wheel hub, had a skateboard wheel on it a was made out of angle iron. The leverage I got with my anorexic 11stone wasn't enough so I got help for a 'bigger' mate. We did it in small amount and crept up on the amount of pull I wanted. If you do go this route, don't do it all in one go, slowly slowly catchy monkey.
and while I'm here in my photobucket account, here's some pics of me in the process of putting the GT wings on (not that I'm biased in any way or trying to sway you in any way
GO GT WINGS..... GO GT WINGS!!!! 
oops, did I say that out allowed )
