bumper mod

got a couple of quick questions for all you fiberglass and molding jedi's...
i got a new aftermarket bumper at a good deal, but it's not quite what i'm looking for. i'd like to modify the section where the muffler is, i want to get the muffler to sit up in a rounded section, but the bumper just has a flat notch for the muffler. i'm guessing fiberglass is the way to go to mold the rounded notch ? what's best to use ? any tricks ? thanks.

Yeah, would have to see bumper but if you don't have to move it. Just mold around it. You gotta sand the back (inside) of the bumper above the muffler. Then take fiberglass cloth with resin. Put it on the backside of the bumper, work with it around the muffler. then either gel kote or bondo to build it up and you can sand it down to a perfect shape. It's a little tricky getting the fiberglass to a good enough position though unless you got some experience. I wouldn't try doing this to a brand new bumper unless you've messed with fiberglass before though.