Decades ago I did try a Group Gripper. Yes, it does improve the rear lock up of the barrel. The Gripper's recoil spring guide rod contains a leaf spring that engages a step on the Gripper's barrel link, pushing up on the link and forcing the barrel up and fully engaging the barrel's top locking lugs with the slide. The downside is reliability. The spring will eventually wear and, although rare, it is possible for it to tie up the barrel link.
I have also used shock buffers. On most 1911's, I think they are a waste of money, they shorten the travel distance of the slide, sometimes enough to affect the slide stop's ability to engage the slide after the last round is fired. The reduced slide travel distance also makes reloading from slide lock nearly impossible via the slingshot method. I think they do have a benefit with 1911's chambered in 10mm Auto as that, in full power form, imparts a lot more rearward momentum into the slide during firing.
Long linking a 1911 barrel will improve lock up, but it also delays unlocking during recoil. The delayed unlocking can result in the edges of the slide's lug recesses dragging on and peening the edges of the barrel's radial lugs. The long link can also result in the bottom lug suffering a hard impact with the receiver's barrel bed, this can cause the bottom lug to crack and break. The bottom edge of the barrel's feed ramp will also be positioned further to the rear at full unlock and this can cause feed jams. I'm not a fan of long linking.
