I use mud flaps on the front. The standard car sized rubber. I did order paintable molded from Mid America and returned them immediately! First I was not driling into my fender. Second, they were made of such hard plastic, one hit and I was sure they would crack OR push themselves into the fender and cause damage. My current are held in place with the existing inner fender liner screws and the flaps are smaller in size but cover enough for me and blend in with the tires. I had to reclear coat all four corners i.e. fenders & rear fascia of my car since it had no flaps from day one.
My car did not have sill protectors from GM the 1997-1998's did not and the previous two owners did not add them. As a result, the drivers side had many fine scratches on it that I could not rub out. So I went with the factory GM stick on type, which just about covered all the scratches. I went with the GM type mainly because they are not too big and obnoxious like most after-market types I have seen and Secondly I wanted it to look factory.