Guys, My W163, ML 270 CDI has pretty banged up bumpers/fenders - I have an opportunity to get an AMG front and rear set complete with arches. My question is this - do I have to fit the arches?

Its really only the bumpers I need to replace but if there going to protrude from the body and look silly then I'll fit the arches as well. Just trying to make my truck look nice with the least amount of extra work. Truck nearly has 100k miles and still pulls like a train, all I ever had to fit was new rear springs and discs and pads. Love this truck

Any help much appreciated