That's the rub, really, what level of difference do you think is enough to warrant the price. For me the price has no bearing on anything, in terms of rating audio gear it is as if you rate the quality of beer by its alcohol content. Higher % must be better, right? Clearly not the case... The only way is to sit down and listen to it in a critical mindset, leaving aside how the component looks, its price and what ever other BS is attached to it. If you can't hear a difference then more power to you, go spend the money on more music.
As for the difference these high power amps make, I've long ago graduated from the usual audiophile hyperbole about the difference in gear. People claiming massive changes due to some piece of wire when it is clearly just BS. Real changes such as better quality components (caps, resistors potentiometers resulting in less distortion), more linear circuits which remain flat into the required load, better quality power supplies which don't fluctuate no matter the demands is what I look for. I used to be a paid-in-full member of the cable club with Stealth Indra's but now I just make my own. I clearly can afford the best but why waste money on something which has no benefits?
Now a 5K$ amp which is properly designed will only give a marginal improvement over a lesser priced amp which is also sufficiently well designed. That is to be expected since you are just throwing money at chasing smaller and smaller improvements. Moving from basic filter PSU's to regulated units gives and easy improvement but the increase in cost is also pretty big. That's why Stax have only once used a regulated PSU in their amps, they simply don't see it as cost efficient. To put this into context lets compare the BHSE vs. our DIY version of the Stax SRM-T2. The T2 is clearly better but if it were a retail product it wouldn't sell for less than 15k$ (probably closer to 20K$) so is it 3-4 times better? Nope but the superiority of the T2 is clear from the first few minutes of listening to it.
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