Saw one review (Z-340) "can shake the pencils off my desk", and a lot of praise, but maybe the smaller driven unit and passive "pressure driver" is not up to the same power as a larger roll-surround driver (which the 2300 has).
The numbers are a lot higher for the 2300, even by the wierd and wonderful way that speaker power is measured.
The sub is actually WORKING, I take it? - driven moderately hard, you can usually feel the vibration, or hear the effect of covering the speaker or port with your hand.
My Tevion NXT 5.1 set replaced a previous 2 speaker set (no sub) that had worked well and served 3 previous systems and countless minor upgrades.
I turned the bass up so I could hear an feel the sub, played a few rounds of some shoot-em-up, then listen to some streaming radio and had to turn it back to more sensible levels, as it was irritating on anything that was more than just booms and bangs.
PS. On a 2.1 set driven through a single jack, select "2 speaker" as the soundcard output mode, using any settuing with a ".1" in it will route the bass to "no connection".