Triggered by some forum discussion about interference risk of operating repeaters in neighbor channels in 6.125kHz channels I was curious about the TX spectrum of my IC-E92. The measurement was done radiated. I checked for neighbor channel interference. You can see the delta values bottom right.

FM wide:

IC-E92 FM wide 1750Hz

FM narrow:

IC-E92 FM narrow 1750Hz

D-Star (only half span screenshot):

IC-E92 D-Star

You can see that D-Star is really the most narrow band mode. Using neighbor frequencies at close QTH still cannot be suggested but at least the interference will be less than for narrow band FM.