Things that I would add to the list of bad ideas:
1.) 8-round magazines for the 1911. I've seen few that finish two days of training without blowing apart. Usually the floor plate dislodges from the base of the magazine, leaving the student standing there with a pistol gummed up with loose rounds, a follower and a spring clogging the ejection port, and a magazine body that they can't get out of the well.
2.) Recoil buffers - get these out of your life! Get them out of your pistols and get them out of your rifles! They never fail to disintegrate under heavy use, rendering the weapon useless until disassembled and cleaned out.
3.) Extended this, and enlarged that. Don't modify guns with oversized slide stops or extended mag release buttons, mercury guide rods or rubber grip sleeves, etc... There's one bit of wisdom that I learned the hard way years ago: There is nothing you can buy, bolt, glue or screw to a gun that will align your sights and press your trigger for you. You cannot spend money on things to make you shoot better, regardless of what our modern American mindset tells us. Marksmanship comes from proper technique and proper practice, and good old fashioned work. . . . Save your money and spend it on training!