I would hold off on drifting those sights or replacing anything for a bit. I Got my G48 on Tuesday and was on the range with it on Wednesday and This is the results of my shooting. Starting with shots to the A zone in the chest at seven yards I noticed things being low left also and had one of my coworkers shoot the upper left diamond. At first he was extremely low left but as he became more deliberate in his shooting the shots migrated north and he was able to put them in the inner white diamond. He then began to shoot the Head A zone and was doing fine until he really tried to run it fast and that's when the ear shot and outside the neck occurred.
I continued with me unscientific shooting from the 7 back to 25 and saw that I continued shooting the pistol to the left and a bit low until I got back to the 25 yard line and began to shoot low right on target, I could understand the low as I have a tendency to see more of the target in my sight picture than I should but shooting right was the issue. You can see that five of my ten rounds went right at 25 yards into the B zone and I flat out slapped the trigger and put one into the C Zone.
So everything is going left and a touch low except in deliberate fire. I then came back to the seven yard line and fired 30 more rounds as deliberately as I could at the left diamond. Because it's so slim compared to everything else I shoot I have found that my trigger finger needs to be to the first knuckle crease in order for me to be accurate.
So low/left is a thing and I'm going to be shooting and carrying this pistol a lot before I'm changing out the stock sights. I was using the crappy stock sights and the ammo was Speer 100 grain frangible.
BTW, as I needed a retention holster for the range I ran a Safariland level two for a G19 and even though it rattles around a bit it worked fine. I'm running a Survival Systems IWB for concealed carry and my total of about four hours carrying like it so far.