i have a 3rd gen pt145 and its always run like a champ. I have no input on the mag release problem, but as for shooting low my gun does that as well (ive seen this problem in other posts about this gun as well). Its an easy fix, either bring up the front post higher in the sight picture, or gently sand down the front post a bit (or have a smith change it out/alter it for you).
"i got the most powerful gun in the world........an .88 magnum. It shoots thru schools......"