I've been running S600 Ferrite motors in my old 3905 Emaxx. They are only $16 and I've gotten about 2x the life than a stock Titan so far and they are still doing fine. I did break them in as instructions directed. I never broke ina Titan.

These will be the last brushed motors mine runs - its BL ready. I've upgraded to 16.8v diffs, UE TI center drives, 3.3 bulks, wheel driveshafts, knuckles and turnbuckles. The S600s were strong enough to twist the rear drive axles.