I can't find R3d 4uerb4ch's post - but wanted to re-mention his way of getting the Quintuple factionalism
Setup a training game. AI team elimination on map 1 (the cube). Use a Plasma rocket launcher. Have SuperStar ability on.
Once you get good at getting/using the plasma (I go back and forth between the SP and the regular) you can easily end the game before the 15 min is up. You'll get on average say 6k points X 3 = 18k points in 5 minutes. It took me roughly 5 hours to go from a 1 to 99. It has saved me many hours - in fact wouldn't have even tried for all 99s without this. Now I level up each faction quicker than it took me to go from 94-99 using the 5-2 5-3 techniques.