I’m pretty sure most if not all of the new lasers have some degree of flare. I also don’t think that is such a big deal. I also think they all probably have a perfectly good 300um spot in the middle of all that flare and halo. I’m pretty sure the current lasers are adequate. I think the problem is that there is no iris to block all the extra stray light they are throwing. So the idea there is simple a little ways in front of the laser make a wall with a very small pinhole. Line the pinhole up so the 300um bright point is roughly in the middle. End result. No flare.
As for how easy it is to switch out the lasers, the answer is very easy. Loosen a screw remove the old one, slide in the new one, then tighten the screw back. The only problem is then you need to recalibrate the printer.