I do not agree with the overall direction of the comments above.
I own 3 quarks 123^2, the first was one of the first batch with XP-E CW bought years ago, one is the XP-G HICRI limited edition, and the last one, which came in the mailbox yesterday, is a Turbo 123^2.
They are not perfect, they show the sings of time and use, but I keep using them, among many other lights.
The first one has been opened and modded, with a XP-E2 3000K, about 2 years ago. I guess that the difference in output between the XP-E and XP-E2 is not so relevant (given the decreased efficiency of a 3000K binning), but the quality of the light for my taste has improved a lot.
The HICRI edition has been opened and I'm waiting for a XP-G2 HICRI that will have enough efficiency difference to make me want to swap the emitter to improve the output.
The Turbo with XP-G has been opened 1 hour ago. I will take the advantage of the big reflector to try some XP-L Hi, or go back to XP-G2 or XP-E2.
So, if you ask me, it's very worth.
But it depends: changing the led won't make a difference in UI, level or runtime.
If you find that you use happily this light, yes, the led swap will bring you relevant difference.
I am not a fan of XM-L leds, too wide beam, I'll move to XP-G2 if I wanted to gain more throw, but keeping a big output and spill; XP-E2 if all you want is a closer beam. XP-L Hi will be even more oriented to throw.