Sorry for the late reply, but I am new here. I enjoy the ballistics of the 45 Super in my smith & wesson 1911's. Several months ago, I called Garey Hindman of Ace Custom about his conversions of 1911's to fire the 45 Super safely. Additionally, I have spoken with Tim Sundles of Buffalo Bore ammo, the "only" current" manufacturer of the 45 Super.
It seems that in early development of the Super, pressures were running about 28k CUP. However, Tim, has developed loads that only produce 21k CUP while producing 1330fps in 185gr, and 1131fps in 230gr. I was believeing this pressure as a typo, but from my emails, he confirmed them to be true, but in protecting his business, refused to say how, saying only that there was a correlation between the primer and his powder, but refusing to reveal anything further.
In my pistols, S&W 5" 1911's, all I have done is to follow another's example in installing a Sprinco Recoil Reduction Rod, which is quite simular to Tom Menck's design from the 90's. It slows down the slide at the end of its travel dramatically to stop it from slamming into the frame. No need for plastic buffers. I also added a Wolffs 20 lbs recoil spring, in finding that my ejected brass was landing about 4 - 6ft from me. Secondarily, an extra power firing pin spring was put in.
Although I have not yet experienced a FTF, I still plan on putting in stronger magazine springs, just to make me feel better.
I have seen no signs of peening, and even with the standard S&W barrels, there are NO signs of brass over pressure signs (the web area of the 45 Super is MUCH STRONGER than regular or +P brass). A fully supported barrel is not nessisary with 45 Super loads, as made by Buffalo Bore ammo/Starline Brass.
However, Sprinco states that you will experience failures with standard pressure ammo as they do not produce enough energy to cycle the slide. Your choice.