I have a 2013 NRS with Akrapovic exhaust, topless, and K&N filter. Had a PowerVision Tuner on it when I bought it. I don't ride at night very often, but the other day I was traveling through town at a steady 30MPH and I looked down and my rear header right at the flange was cherry hot.
Well, I was wanting a Target Tune anyway, so I ordered one, installed it today, as well as the FuelMoto map they provided. Went for a ride, and I thought the glowing exhaust was gone (my decel pops and gurgling were gone!), but I was riding down a long city street, 2nd gear, 40MPH, 4K RPM, very light throttle to maintain speed, and my rear header started glowing again. Not nearly as bright as before, but definitely a red glow.
Ran a fairly long AutoTune session - Interstate, country highway, city stop and go, steady low speed, and tried to hit as much of the map as possible. Loaded the new tune and took another ride, 2nd gear 40MPH, 4K RPM, and still had a glow.
Did a quick AutoTune session focusing on the 4K RPM range in 2nd gear, and then loaded that new tune. Still glows, but seemed dimmer than before. I'm in the process of adding fuel to the map in the 3750 and 4000 RPM range at 7, 10, and 15% throttle position. I'll see what that does tomorrow night.
I tend to lean towards those saying it is just normal for these pipes, because it seems to happen no matter what I do.
Now my PV screen blanking out...That's another battle I'm going to fight tomorrow as well.