There was an earlier thread talking about this, but I wanted to share my experience on replacing not one, but two of them in my 819. I previously had a 721 and replaced the front seat base 2-3 times, all of which were a real PITA!
This time I had my trusty 1/2" chisel and hammer along with a utility knife to trim the carpet and a small set of vise grips to pull the pieces out. BUT, I add a multi tool!!! The first one I did took maybe 30 minutes since I was using the multi tool, the second one 15-20 minutes. On the second one I did not trim the carpet first, I cut down with the multi tool and then used the chisel. I pulled out maybe 20% of the base this way, then I made more cuts, hammered the chisel down and pulled the remaining 80% out in one piece.
This was a heckuva lot easier than chisel only!!
Sorry no cool video.