Monk. I bought my 5-4 reducer at the local Truck pro store. It's a big diesel supply store. Their's has about a 4 inch leg on each side of the reducer so you can trim it to the length you need.
The pipe looks nice Jason. I removed the air on mine and wanted to go 5 all the way but my car has a mid plate so I had to notch the plate to fit the 4 through it.