I used a thin ribbed rubber floor runner that Ace Hardware has on a roll. It was almost identical to what my Boler
had originally. I had the original piece of aluminum trim to finish the edges around the guard.
Costwise - I probably paid close to 75-85 bucks for the mat, contact cement and other odds and ends.
If I didn't have the trim I would have gone for taping and rolling/spraying on some kind of truckbed liner so it looked neat.
It was difficult to cut the rubber runner neatly/evenly, and the contact cement deformed it slightly(eventually it cured and shrank back into it's original shape) making it hard to place exactly where I wanted too.
The rubber mat was also not easy to make a template for with the curves of the egg - I *think* most people here have been going the way of truckbed liner due to the relatively easy application and availability.