Price does not indicate the design and parts quality. I can make a great looking chassis and put crap inside and sell it for much more that a cardboard box chassis. But I can also make a product and put it into a cardboard box that would also sound great.
When I look at "expensive" components, I rarely see high quality parts such as custom transformers, capacitors and resistors. I see mostly aluminum chassis milled from thick aluminum. Looks great but sounds better than the less expensive stuff.
When I modify something I start with the power supply and filter the AC first, then improve the capacitors and resistors. Plus point-to-point wiring. When you find something like that, you will hear the differences within 30 seconds.