so I hear two bass components the distorted electric piano bass responding to velocity/dynamic playing and the low saw wave sub bass that has a slow lfo modulating the filter and the pitch a la vibrato w\both with a very shallow depth (i.e.the result is minuscule but effective.....)
Well, that "growl" is a bit subtle. You can achieve this kind of effect subtly in a large variety of ways. Depends on what you are initially using to generate the bass. If you were using an analog synth like Massive or something, I would just put a filter on the osc with a fast LFO on the cutoff or something. If you are using an actual bass or sampled bass, then I would simply put it through some subtle distortion (I would use Guitar Rig). Hope that helps.