Plus P is probably OK (check the firearm's owner's manual). It is only a modest increase over standard pressure. .45 Super is, IMO, far too hot for an unmodified pistol. It would probably not blow it up, but its component life will be short, assuming it even functions. If you look at Ace Custom's (the pioneer in this area) site, you will find that all the pistols so chambered are fairly heavily modified, with stiffer recoil springs and other parts "beefed up."