To be honest even a entry level stax like my stax lambda signature destroys the HEKstealth and HE1000 V2 in most area's except maybe bass quantity/impact.@Tyler Durden: You started this.
I bought a pre-owned SR-009 two? years ago and my expectations were sky high. Wow! My first TOP OF THE LINE headphones (ok previous TOTL) headphones!
....and I was quite dissapointed when I first heard the SR-009 because I thought, well nice, maybe very nice, but still sounds "more or less" like any other headphones I had at this time (HE1kV2, Focal Clear OG, Dan Clark Noire). I was so naive to think, ok a former 5.5?k€ headphone had to sound as not from this earth, as something truely enlightning. I know that was totally silly but that sometimes the brain works (or maybe only mine ).
Now, I still have the SR-009 and I love them. They are my go to headphones for detailed, open sound and they are also super comfy for me. They always fight with the HE1kV2 (similar type of sound signature, for me) for play time and most times win.
For me the SR-009 costs now about what they are worth compared to other more current headphones, no way I would have paid the original price.
So I think you are in for a treat.
Stax lambda definately sounds more open than any hifiman I tried even the Susvara which I owned for 2 months, Susvara couldn't keep up with the detail and speed of the stax lambda signature not even close imo.