Not the easiest of tutorials but its a fun one..

More specifically for Mustangs 96-98.. But i'm sure its easily adaptable to any other grilles that have similar mounting emblems.

I love batman so i chose the logo for my grille but you're only limited to your creative skill as far as what you decide to replace your pony with.

There are many ways this could have been done but i was limited on tools, knowledge, and how it was going to work in the first place..

Basically you'll need :

A sheet of aluminum(or sheet metal though i'm not sure how much easier it is to work with) You can buy one at Home Depot, Builder Square, Lowes, Ace etc...
Assorted files to sand down the grooves and corners
A vice to hold the sheet in
A jigsaw with metal blades
Coping Saw to get into the hard to reach places..Safety glasses cause the shavings will get everywhere..
Epoxy for metal, plastic, aluminum...
A marker and ruler..
Metal polish to make it shine
Patience and elbow grease!!

Step 1: Removal..

Pop the hood for easier access to the two philip head screws holding the bracket to the grille. Remove them and the bracket comes up and off.

Step 2: Template

Sketch out your favorite symbol but make sure you keep in mind the dimensions must stay within your grilles given space.

I'd take a pencil and sketch it first before you go at it with a permanent marker like i did... oops

Step 3: Elbow Grease..

Put on your safety glasses, and place your template in a vice. Take the jigsaw and shave off as big of pieces as you can without cutting too close to your design and ruining it.

Then take your coping saw and get in as close as possible. Then take your files and sand down to the lines you sketched on the sheet. Try and be steady handed as you can.

Step 4: SHINY!!

After you've sanded down your design just how you like it, it's time to make it shine.

I used Mother's Mag And Aluminum Polish and gave it about 3 coats. The more you do it... the more it'll shine.

Step 5: This Part Is Tricky..

Originally i was going to cut the pony to pieces and just use the backing to mount my new design to but after inspection i thought it would just be easier to remove the horse from the bracket with a flathead screwdriver and a hammer.

Carefully place the flathead screwdriver between the horse and bracket right on the spot where it looks riveted. It should come off and just hammer flat the bracket for remounting.

Step 6: Mounting It Back on to the Bracket

Read the instructions for the epoxy and how it mixes, and ready your bracket and cutout.

Adhere them and aim to get your design as centered as possible to keep it from looking odd when you remount it.

My design was rushed so i didnt clean up my batman logo enough but i figured i can always remove it and sand it down some more as can you.

Step 7: Remount and ENJOY!!

Install your design back onto the car running the screws back in, close the hood, and stand back for the grand view.

Hope this wasn't too confusing cause trying to figure out how to do it was.. :P