Very hard to get flaps to fit that don't need drilling ...the wider you go they will need to be drilled.
I went for mid sized ones that clip on they look gay but they come on and off as the weather gets bad I just got them to stop the rear arches getting peppered with stones
Drilling the bottom of a car is a big no no for me as it will never be right
There was a place in the states that did wide ones if I remember correctly carlo put up a post a few years ago about them amor something ....they claimed no drilling required and they were wide rally style
Yes Keith hats them I put them on the s204 and there stupid money 120 sterling . But they still don't fit with out fixing to the car . I had to make stainless steel brackets and bolt the to the original mounting points on the car . A lot of work but worth it not to drill holes in the car anywhere