The only STAX farts I've had is when they were sealed 100%...any movement would cause them, way too annoying with fully sealed pads. Since taking 2 segments out of the Fun-tack ring there is zero STAX farts and noticeable increase in bass. I do listen at a lower level, and only have +3.5db lower shelf @57Hz & +1.5db peak @ 82Hz. Bass from the modded L300 Limited is 404LE level, but has better overall sound with larger presentation space and much better imaging.
If you are getting that from current setup, you will get it and more from a more powerful setup. The better amps than the SRM-323S (that's what I started off with) will get you more bass impact and punch with a fuller, smoother sound and better extension. My L300 Limited hits absolutely hard and solid on my setup, outdoing any of the planar magnetics I've heard from Audeze. Best bass I've heard period has been from my rig and a STAX SR-007 Mark2, the modded L300 Limiteds are right behind it.