I put one in my '09 Challenger. I got it from Gunslinger and it was a simple 10 minute installation. The one I got was just the handle assembly. There were also kits available that had the handle and linkage assembly. I sort of wish I'd spent the extra money (over 2X what a handle alone cost), for the complete kit as the throw is too long with the factory setup in my car, and I'd have liked to update to make the throw shorter and therefore make it quicker to shift.
There were instructions with the handle to release the clips for the boot from the console, then there were 2 acorn nuts holding the handle to the linkage, a twist tie was included with the handle to hold the upper part of the boot to the shifter shaft. As I mentioned before, simple quick installation with just the handle. I'm sure the handle with linkage would be more involved to install.
IIRC Gunslinger sold out to some other company a year or so ago.