Idunno about a red badge on a yellow car, but I think red on aquamarine pearl would contrast pretty nicely.
My dad's mk1 came with an extra badge (hidden under the seat . . . go figure). I had it on my 2's nose until the glue gave out.
But I was able to recover the badge, so no harm done . . . I'd like to see a red mk3 emblem on a dark car . . .