I think it doesn't work very well. If I had to have it I assume it would look okay on a white, AR or NFB car since those are the colors closest to the flags color. Otherwise, it might as well be a graphics sticker that says Injun.. or whatever they say.
Just my opinion, but probably best when either the red, the white or the blue is an exact match for the color of the car. Those blues are too far apart, the red was closer and of course no Elises in white in the US, at least not yet anyway...
Otherwise, no problem with the flag being there, seen it on the mini, and the austin powers cars (Shaguar) etc.
Take note though. It needs to be drawn correctly as it is on the mini pic. The red diagonals are not in the middle, the white vertical and horizontal lines are wider than the diagons... etc. Brits (like me) will notice if it is'nt done right
BTW all the red diagonals are offset witin the white line, ALL towards the anit-clockwise direction. This does mean that one sise of the car signifies an SOS ( the flag is upside down).
I'd leave the UJ bit for the cars that are supposed to be what they what they really can never be.
It's too "pop" for the Elise, imo.
i'll admit that the BEON Cooper S is a serious bit of kit when driven well.