Thomastrouble,
Assuming that you are going to double the power output of 150W at 8ohms as the 3.6 will present a 4ohm load which should increase power output of the Sim to close to if not 300W, based on this being solid amplification which the Sim is you should be fine running the 3.6's and your current Sim. If you felt the need for more power you could always add and external amplifier and use the Sim as more of a processor or if the ability is there you could actually use the Sim to power the highs or lows and an outboard amplifier to actually set up to biamp the speakers.
Assuming that you are going to double the power output of 150W at 8ohms as the 3.6 will present a 4ohm load which should increase power output of the Sim to close to if not 300W, based on this being solid amplification which the Sim is you should be fine running the 3.6's and your current Sim. If you felt the need for more power you could always add and external amplifier and use the Sim as more of a processor or if the ability is there you could actually use the Sim to power the highs or lows and an outboard amplifier to actually set up to biamp the speakers.