I added the same guards, and my downpipe guard was an absolute devil to get in place and reassemble the lower cowl. It just didn't want to stay in place, and when it did it seemed like it was interfering with the cowl lining up on the bottom for the plastic screw inserts. Finally got it though and it does add some peace of mind riding in the Texas Hill Country with all the limestone pieces everywhere being thrown from the cager's tires.
Enjoy!