My top system rig is as follows:
* RME ADI-2 DAC ($1k, bought when they first came out)
* NAD C275BEE Stereo amp (bought factory refurbished for under $900 for my HT and repurposed for my estat rig - brand new runs ~$1.3k)
* Mjolnir Audio SRD-7 electrostatic transformer (~$740)
* STAX SR-L300 Limited, modded (~$1.1k, L700 pads and headband and blu-tak mod)
* Furman M-8x AR Line Voltage regulator (~$560)
* Benchmark audio and Blue Jeans Cable (less than ~$150 total for everything used)
* SANUS 15 PU rack with swivel castors (~$240)
So the 'base' system rig cost me around $4.7k
Also added in the system is stuff I already had and added for more functionality: OPPO BDP-95 multi-media player, TASCAM MH-8 headphone amp, an auxillary 22" ASUS IPS display mounted on a swing arm. Also vented rack block off panels were added for aesthetics and create 'solid' front face to the rack unit.
The L300 Limiteds with L700 headband and pads [with pads blu-tak sealed] on the rig are something that brings both great subbass and neutral, full tone with a somewhat bright but non-fatiguing sound signature. Extremely detailed and transient speed beyond most anything else besides other higher end e-stats, with most excellent separation and a nice sense of 3D space to its sound - great for gaming and movies. Has some of my favorite bass found in any headphone yet also punchy, extremely clean and clear sound. Treble is very detailed and energetic but non-fatiguing. Fairly neutral overall with just a tad more than neutral bass.
Nearest thing to them which I've heard is the Focal Clear, but the Clear has less low end, a more intimate presentation that is also relaxed a bit more, and doesn't have that e-stat speed/layering presentation.
Here's the system with STAX SR-404 Limiteds I briefly owned:
And my modded SR-L300 Limiteds: