That's a tough one to answer, as audio is very subjective and everyone places different levels of value on items and experiences. I'll try to explain the best I can though.

Arya Stealth already sounds phenomenal, and so do the majority of headphones >$500. When you start getting into high-end audio, diminishing returns are very real. I wouldn't be able to say that Susvara sounds as much better than Arya as going from HE400 to Arya, because once you reach a certain level of sound quality, it becomes more about detail and flavor, so to speak.

The detail and sound quality are phenomenal, and is absolutely the best I have ever heard from headphones. However, if I were solely chasing better sound quality, I would've stopped at HE6se or LCD-X and called it a day. With music being so subjective and such an emotional experience, I find the Susvara to be worth it for me. I also made sure to get them at a discounted price which will ensure minimal loss if I ever decided to sell.

They're worth it to me because the improvement of little nuances in sound are the difference between thinking "this sounds really good," and "I feel this like never before, this is incredible." When you experience detail brought out in music in such a way that sounds so natural, smooth, and enjoyable, it really does make a difference. For me anyways.

If I had to put a number on it, which I don't even know how to accurately do so, I'd say from 0-100, LCD-X and Arya are an 80, with Susvara being a 90. I say 90 because I don't know whether or not there's a more enjoyable headphone that I don't know about, so I can't be certain.

Once you reach summit-fi levels of audio, it really just becomes more about finding a sound you like that reproduces music in the best way possible for your ears. It's a completely unnecessary, and honestly ridiculous amount of money to spend on headphones, but it is what it is. There are more destructive hobbies and habits for sure.

Having heard many headphones ranging from free to now $6k, I can say with a fair bit of confidence that the peak before highly diminishing returns is at around the $1k price point. So think LCD-X, Arya Stealth (on sale), Focal Clear OG, etc. Those get you top shelf sound without reaching the point of ridiculousness.

Tl;dr: They sound better, but it's hard to say "how much." To me, it's considerably more enjoyable, but to others, maybe not. Sorry for such a long response.

Not yet. Currently at the Susvara stage and looking at tubes. It's a pretty deep hole! Lots of fun though, and my wife enjoys it, so a win-win.

Got the same deal! Absolute STEAL.

Right now an S.M.S.L. SH-9, but they definitely need more power. Looking at the SP400 as it delivers an obscene amount of power. 12W at 16 Ohm versus 6 on the SH-9.

They still sound really good on the SH-9 though.

Yeah I saw some videos of some using chicken wire and some other stuff from Walmart, and I was like ehhh no. One scratch and my OCD is ready to burn it all to the ground lmao

Haha it does sort of look like that

Nothing at the moment, but I'm going to be adding some fabric in between.

Found mine on eBay. There's someone there selling them for $20. Got them in like three days (US) and it took less than five minutes. Super quick and worth every penny. Really gives them a more open sound.

Search for "Hifiman Grill Mod Replacement - High End CNC Aerospace Stainless steel - Pair" and you'll find them. The quality is stock level good. Comes in multiple finish colors too.

Love this. My Rainy Day kit just arrived yesterday!