Oh, I get what you're saying, now. Sorry.
At the moment, I only have the DACport LX and the DACmini CX (with 1-Ohm mod).
I'm really surprised that the 1-Ohm mod is available for the DACport LX - that doesn't seem to be the case just looking at their website, but I guess it proves that the LX has the same analog circuits as the non-LX version of the DACport - without the volume control.
So what do you think about going for a "cooler" (less warm), more neutral signature - by getting the 1-Ohm mod. Do you wish your Heir Audio IEMs sounded less warm, more neutral, and a little brighter? If not, I'd say don't send the LX in for the upgrade.
In the past, I've had three other DACS - all relatively inexpensive - nothing special: The $49 Stoner Acoustics UDS100, the $149 JDS Labs Standalone Objective DAC (a.k.a ODAC), and the iBasso DB2 Boomslang2 portable balanced DAC - the worst of the three, in my opinion - the DB2 was just way too dark - especially for my LCD-2 - but mostly it's just a matter of personal taste, as some people like the DB2. I returned it for a full refund under iBasso's 30-day trial guarantee.
I also returned the ODAC to JDS Labs, paying a 15% restocking fee - I found it to be "screechy" in the treble with my laptop's power supply - but not with other machine's power supplies. Thing is, the DACport LX has never had a problem with quality of USB power on any laptop or PC with which I've used it, so their suggestion that I purchase and use a powered USB hub with the ODAC was out of the question. It wouldn't be portable if I have to use my laptop near an AC outlet just to satisfy the ODAC's finicky power requirements.
The Stoner Acoustics UDS100 is a much better ESS 9018 DAC than the Obejective DAC, in my opinion - and less than half the price. But I it bundled with the sale of a Meier Stepdance, to a friend of mine, who had neither DAC nor amp.
I really feel content with the DACport LX - which basically sounds 99% as good as the DACmini's DAC. I'm not even sure the DACmini's DAC is better, but a few people seem to think so. I can't really hear a difference. I'm good with either one of them.
Enjoy it!
Mike