T-REX makes a nice billet grille insert, but the one they make for '06+ Rangers can only be installed by cutting out the middle of the stock grille and screwing the insert inside, leaving some ugly "tabs" around the edges.
I'm going to show you how I used an older style ('04-'05?) two-piece Ranger grille and modified it to fit the new insert. I did this two years ago and haven't had any issues with it.
Tools:
-drill and drill bits
-pliers
-small hand saw
-sandpaper
-wrenches
Materials
-T-REX grille insert
-two-piece Ranger grille
-length of 1" aluminum flat bar stock
-small bolts and nuts
-paint
Remove the center of the two-piece grille. Sand and paint the outer frame whatever color you want. I got a black grille insert and considered painting the frame black, but ended up going with a color-matched white.
Once the paint dries, you're going to need to do some trimming. Flip the frame over. You'll notice there are a lot of small tabs around the inside of the frame. Cut off all but four of these. The ones marked in yellow are the ones you want to keep. You're going to mount the insert by bolting two strips of aluminum to these tabs, then bolting the insert to the aluminum.
Drill a hole through each of the tabs.
Cut two strips of aluminum to fit across the tabs. Mark and drill holes in the aluminum, then bolt the aluminum strips to the tabs.
Test fit the insert. Carefully mark where to drill through the mounting brackets on the insert onto the aluminum strips. Drill your holes then do another test fit.
My insert needed a little modification to fit snug. I had to bend a few of the mounting tabs a little to make them line up. Once you're satisfied with the fit, bolt in the insert but don't tighten anything yet. Make sure everything looks good, then remove the insert and aluminum strips.
Sand and paint the aluminum pieces to match your insert, black in my case. Once the paint dries, assemble and tighten everything. From here, the grille assembly just snaps and screws onto the front of your truck like normal.
Nice and clean, and no ugly exposed cut pieces.
I know this is a fairly specific write up, but hopefully it will encourage others to experiment a little!