Eddie TX
BLA have been in business for a long time. Given that their customers are primarily audio engineers whose job is to evaluate sound quality, I'd say that's a pretty good indication of the value of their services.
Have to be careful with that assessment. I've known more than a few audio engineers that drink audiophile koolaid. One guy swears his high dollar power cord makes his amp sound better. He thinks some how that not only does his extremely high quality amp not filter the power well, but that the problem is the last 3 feet of cable in the studio, not the thousands of feet in the wall or the thousands of miles of aluminium/steel going to the generator. Just because someone is an audio engineer doesn't mean they don't listen with their wallet at times, or exhibit wishful thinking.
If you want some good talk on this sort of thing
Dr. Floyd Toole has a excellent talk about the necessity of blind testing in subjective listening and verifying the results with objective measurements.
So at the very least I'd need to see a blind test where someone demonstrates they can pick out their modded kit reliably before I'm interested. Then to really be convinced I need to see measurements to make sure that it actually made the sound better, not just different.
Have to be careful on that last one, as you can find expensive products that change the sound... for the worse. Like you can get flat speaker cables. They have individual thin wires laid parallel to each other in a dielectric. You can hear them all right... because they have a ton of capacitance and jack the signal right up. You get some serious HF rolloff. Problem is people will hear the difference, see the price tag, and decide they sound more "laid back" and less "fatiguing" which is probably true, but can be replicated with something costing 0.1% of the price if that's what you want.