wow, those suckers are loud!! Good thing you don't live next door to me!!! LOL
One thing I noticed on your first video is the shot of the differential and exhaust going over it. It looks like the pipe was bent into a "U", then welded to the tail pipe and muffler? That's a real flow killer the way the pipes are stretched and cobbled together. My truck is the same way. Didn't notice it until some time later. Realy ticked my off the way the guy butchered my new muffler install. Oh well.