XBF, welcome. Your post is a bit surprising and disturbing. If you have your system calibrated correctly, playing at 0dB means that the maximum level of 105dB for movie sound specifications is possible. Very few home listeners use this 0dB "reference" level, since it's considered entirely too loud for continuous use, and more commonly a level of -10dB or so is used.
Getting a 200 watt separate amplifier would add only about 2dB to the maximum output level at which your speakers can now play with your 3311. For example, if 107dB is now possible, a just barely noticeably different 109dB could be reached. Your 3311 should have all the power capacity needed to drive your speakers at levels which won't cause permanent damage to your hearing; a separate amplifier shouldn't be needed.
On the chance that your system isn't correctly calibrated at 0dB, but is in fact low, you can try using +2dB or +3dB instead of 0 to see if the sound level is more satisfactory with this "free upgrade".
