I'm surprised at Wings crashing when you try to export an OBJ of 71k polys. I've just tried importing Vicky 3 duplicating her and exporting both as an OBJ of 150k polys with no problems. If you want to get rid of ngons don't triangulate, select all faces then tessalate/quadrangulate.You could also use Cleanup on the object to get rid of extremely short edges and unconnected vertexes.