got under the car again today, removed the undertray and took some pictures. found a way which i believe the Japs have used to mount a brace to the front. theres 7 screws that screw into the sub-frame, from the six on the sides a frame could be made with only the middle and cross sections having to be slightly curved. this would allow a one piece to be made and bolted in a once,yet you would lose the undertray. the piping should have to be big or thick so in theory it could mount a flat sheet or anything to made a splitter. better then stock as its curved and odd shaped.
first picture shows the subframe
second highlights in red where the undertray bolted in and the mounting points that would be used. yellow lines are the brace, just done it roughly on paint using all 6 points, it could just be 4 on any of the even points even linking to the 7th which is in the middle at the top end by the bumper. in the centre was a bolting plate that it could be bolted to for extra strength or just go over it.
im guessing the GT and other models have used the same subframe so in theory it could fit that
i might have to sell the car so one would def be made and if theres interest i could send it off to be copied or just pass it on to a twingo owner to use, but thats worse case. if we're keeping the car i would take my time over it and wait till a few would like one made
**sorry my bad, just realised the Jap one starts from the last 2 bolts (bottem of drawn brace) and heads a bit lower, didnt really look under the car in that area so will take a pic tomorrow to see where it could bolt into. would it be better to have the brace under the engine like drawn or after the engine/front passenger area like the Jap one?? **