I had a chance to run about 120 rounds through my Beretta 96D with the 20lb spring yesterday. It worked flawlessly. I guess the magazine springs were the issue after all. There is a slight difference in felt recoil. I wasn't able to put the gun on the timer to see if my splits changed any, but the sights seemed to fall into place a little quicker. Feelings can be deceptive, but it felt faster. The timer will tell the tale when I get a chance.
I have been talking to some people about running a spring that is 50% stronger than the stock spring and some have expressed concern over negative wear effects. The force of the slide going back into battery could cause abnormal wear issues. I put in an e-mail to Beretta asking them that specifically, and their reply basically said they do not recommend use of non-factory parts, and that a heavier spring could cause function issues, but did not say whether or not it would cause durability issues.
I guess my 96D will be the test bed to see how it works out. As long as the gun remains functional, I don't plan on moving back to a lighter spring. The below video is at 1/8th speed. It is a little too tight, but you get the idea. The brass was ejecting nearly straight up and hitting the ceiling.
There won't be a training update associated with those 120 rounds since really all I did was rather pointless mag dumps down range at varying shooting speeds. I didn't have any of my usual training targets with me to run Dot Torture or anything like that. They only really training related thing I did was finish up with 10 rounds at a 3"x5" card at 10 yards.