If it's the E2030 muffler, then whatever OS's intention may have been, it's tuned. At least on the FP 20 (which uses the same muffler) the Brett-Buck recommended set up is to leave it as it is. I suspect that he feels the same way on the LA 25.
I use stock E2030 mufflers on both my LA 25 and my FP 20, and I couldn't be happier.