I am quite impressed with 301 scutlping so far. I have it working now on 995,328 real polygons at useable speed (but a little bit slow). Even while using "image ink" it was working perfectly. I pressed "D" once more to increase to 3,981,312 real polygons and was still able to sculpt although not in real time. Then i hid a lot of the polygons and had no problem sculpting at about 1,200,000 polygons. The trick was to first click/press the mouse or style down. Then wait for a slight pause until the mesh started to sculpt. Then it was sculpting quite fluidly with nice smooth results until i ended the stroke. Lastly i revealed the full 4M mesh and tried to sculpt with this "hold and pause" method but Modo gave me a warning that i was dangerously low on resources... Most importantly through all this was
Modo did not crash 
!!!
I think the poly count limit is due to my hardware (dual core 3.6GHz P4 with 2Gb Ram). If i had more RAM i think i definitely could have gone to higher polycounts...
shorty